It was a time when pirates ruled the seas. Several bands of pirates were battling over the great hidden treasure, One Piece, which was left by the now legendary pirate captain, Gold Roger. There was a young boy who admired the pirates, his name was Monkey D. Luffy. One day, he mistakenly eats the devil's fruit and turns himself into a rubber human being.
Ten years have passed since that incident. Luffy sets out to sail all alone. He sets out to become a great pirate captain and that's when his great adventure begins. "I'm going to be the Pirate King! I'm going to get One Piece!".
The Straw Hats have arrived at a volcanic island that does not show on the New World Log Pose. Luffy in his enthusiasm votes to go to the island, though most of his crew are reluctant to go. The crew than receives a distress call from someone on the island who is being attacked by a samurai. They then draw sticks on who will go with Luffy and who will stay on the ship, with Zoro, Robin and Usopp coming with Luffy. With the help of Nami's clouds, the scouting group arrive at the main entrance which Zoro cuts down with ease. The group wanders the area seeing the whole place being constantly on fire and wondering what happened here. Their exploration is suddenly cut short when they encounter a Dragon looking hungrily at them.
At Raijin Island, Smoker and Tashigi intercept the distress call that Luffy picked up and order the G-5 Marines to set a course for Punk Hazard
Luffy and Zoro starts fighting the dragon, which is shown to be able to speak and breathe fire. Luffy rockets up to the dragon's back, discovering the presence of a pair of legs. Luffy manages to make the dragon chew its own wing, making it fall. Zoro takes the opportunity to jump into the air with Usopp's trampolina and decapitates the dragon.
Meanwhile, Nami, Chopper, Franky, Brook, and Sanji are all asleep due to a sleeping gas and are abducted by men in hazmat suits.
Luffy, Zoro, Usopp, and Robin are standing near the dead dragon that Zoro killed and Luffy is trying to pull out the man who is stuck in the dragon's body. Luffy succeeds by pulling out only the legs, making everyone think that he killed the man. However, the legs are alive and they run away trying to look for a Shichibukai. Luffy runs after him and gets stuck to the legs after the legs fall on top of him.
Elsewhere, the Straw Hats who were captured by the people in the hazmat suits (Sanji, Nami, Chopper, and Franky) are in a prison cell and were shown to a gaseous figure known as "Master" who is very interested in Franky. They wake up minutes later in a cell and try to figure out how to get out. They then see a man's head which was cut into pieces and put it together. The head is alive and it tells them that his body was cut into pieces by a Shichibukai and he feels shameful for not getting killed after getting sliced.
Back with Luffy's group, Usopp sees a harpy girl on top of a burned down building, but after he yells for everyone to look, she disappears suddenly. They then approach a lake that separates the fiery and icy halves of Punk Hazard. Luffy befriends a centaur that thought that Luffy was one of his kind. The people of Punk Hazard who work for Master see Luffy's group and tell the harpy girl about them.
Franky, Sanji, Nami and Chopper are surprised that the samurai is still alive after being cut. He is surprised that Nami talks in such a direct manner and dresses in revealing outfits but says that he likes it. He then finds out that they are pirates and says that he doesn't want to go with them because he hates pirates. He says that the reason he went to the island was to find his son Franky then blasts a hole in the wall using his Radical Beam and they escape, running into a room filled with giant children.
Luffy races against the centaur he befriended. Usopp contacts Brook and Brook tells him that Nami, Sanji, Franky, and Chopper were captured. The centaur gets a call from his comrades and they tell him that Luffy is the enemy. Luffy beats him up and Robin handles the other centaur that comes to help. The Straw Hats notice that the Den Den Mushi the centaurs were using had CC written on it.
The Master gets news that the Straw Hats escaped and that one of them can shoot laser beams like the Pacifistas. He also learns that they are in the biscuits room with the giant kids. He also finds out that the Marines are arriving and tells his men to send out poison gas to stop them from landing. The G-5 men start suffocating from the gas so they put on gas masks. Smoker then explains that the island was the battleground for Aokiji and Akainu when they fought for for the title of Fleet Admiral two years ago.
Nami's group who escaped the prison cell end up in the Biscuits Room, where they find giant children. The children play with Chopper and Franky for a moment, but are scared when the samurai head asks if they have seen a boy named Momonosuke. The hazmat suit soldiers arrive and attempt to capture Nami's group, and the pirates run away. Meanwhile, Usopp makes a banana boat so Luffy's group can get across from the fire side of Punk Hazard to the snow side of the island. The centaur who Luffy beat earlier sees them, and tells his boss that the Straw Hats are heading to the snow part of Punk Hazard.
Back to the mysterious facility, Nami's group decide to stay and save the children, and defeat the hazmat suit soldiers. Meanwhile, on the frozen side of the island Brook is building snowmen and is suddenly attacked by the samurai's torso just after his snowmen are complete.
At the lake, Luffy's group have been attacked by Brownbeard and his centaur unit who's job was to intercept and eliminate any obvious intruders.
In the lab, Chopper is fighting off the hazmat soldiers who were attempting to get into his, Nami and the children's way. Sanji and Franky continue to fight off their hazmat soldiers and discovers that they look like sheep. Meanwhile outside of the lab, Brook is seen fighting against the sword wielding torso and after trying to talk to it, gives up and runs away from it.
With the G-5 marines and Smoker, the group blasts their way into the island and discovers a hidden river which they quickly enters, unaware that the river was being monitored. At the Lab, a hazmat soldier warns "Master" that the marines have almost reached the harbor. Master says he doesn't want to reveal himself to them, but his accomplice says he will greet them instead. The G-5 Marines finally reaches the shore and after Smoker rings the doorbell the marines decides to blow the door open. This was interrupted when the door suddenly opens and out comes the former supernova, Trafalgar Law. His sudden appearance makes all the marines except for Smoker and Tashigi scared. Tashigi claims he is now part of the Shichibukai after Law gave the World Government 100 pirate hearts in exchange for the position. Smoker then demands to know why Law is on the island at all since no one is permitted to set foot on the island, to which Law calmly replies with that Smoker and the marines are not allowed to enter here either.
Chopper and Nami get the children to a room with people frozen in it. Franky, Sanji and the samurai start to make their way towards Nami and Chopper. Luffy, Zoro, Usopp and Robin get attacked by the centaurs. The centaurs attempt to sink their banana boat. Smoker and Tashigi claim that the signal from earlier came from Punk Hazard and Trafalgar Law states that the Marines often tend to forge messages. The Straw Hat Pirates and the children see Law and the Marines, at the sight of them they run back into the building. Law uses Room and Tact to lift a marine warship in order to prevent the marines' escape. Smoker and Law then prepare to fight.
Luffy, Zoro, Usopp and Robin try to get to the ice side of Punk Hazard but their ship gets capsized by Brownbeard. As Brownbeard's troop prepares attack them again, Zoro gets ready to destroy their bullets but gets dragged down by sharks. At the last second, Brook saves them and defeats Brownbeard's shooters. Once Luffy and the gang got out of the freezing water after killing the sharks, they opted to take the centaur's warm coats.
The Straw Hats who rescued the children attempt to go back into the building to find another escape route, but their "hearts" get switched by Law, making them swap bodies. Law then returns his attention to the marines and destroys their ship. The G-5 marines attempt to contact marine headquarters about Law but he takes away all their Den Den Mushi. Smoker then fights Law and warns his men to stay back from the fight unless they want to get cut to pieces (which they did). Feeling useless in the situation, Tashigi attempts to strike the Shichibukai but was promptly bisected.
Law was going to to cut up Tashigi into little pieces but Smoker saved her and started fighting against Law. Luffy, Zoro, Robin and Usopp are riding on top of Brownbeard after defeating him and his centaurs and stealing their coats and are heading towards the building Brook told them about. Nami, Sanji, Franky, Chopper, the kids and the samurai head try to escape from the Law and the Marines while figuring out what Law did to them. In front of the labratory, Law defeated Smoker by taking his heart.
Tashigi tries to see what happened in the fight. Luffy's group sees the flying warship. Luffy sees Law and thanks him for saving him two years ago. Law says that they aren't friends and Luffy agrees since they were both after One Piece. Law remembers the past between him and Luffy when Law saved him at Marineford. Luffy sees Smoker on the ground. Tashigi cries over Smokers body and attempts to kill Law but he switches their hearts. Meanwhile, the kids from the lab complain about the cold so the samurai uses his devil fruit to give the kids and the Straw Hats warm clothes. Luffy's group then meets up with the other group behind the lab. While going over what happened Robin reveals that Law became a Shichibukai two years ago and the samurai reveals that Law is the one who cut him in thirds and reunites with his legs. Law meets up with Caesar Clown who Smoker speculated was behind everything on the island.
G-5 discusses the possibilities of Caesar Clown being behind the unusual events at the island. Brownbeard briefs Luffy about an incident that took place two years ago. Smoker reveals Caesar's true intentions.
The children and the Straw Hats are in a cave with Brownbeard tied up talking about the Master. Zoro, Sanji and Brook go to look for Kin'emon, who had gone to look for his torso that Brook saw roll towards the ocean. The children start complaining and falling over from pain. Chopper, who had been testing them for any sicknesses, revealed that they had been given a highly addictive drug and were suffering from withdrawal symptoms. The children start attacking the Straw Hats, who can't fight back without injuring the children. Usopp eventually is able to put them to sleep with one of his new attacks. Back in the lab, Law gave Smoker's heart to Caesar, who had sent the Yeti Cool Brothers to deal with the Straw Hats. The Yeti Cool Brothers are then shown talking to each other while Zoro, Sanji and Brook were lying unconscious nearby.
The Yeti Cool Brothers are making their way to the destroyed lab where the Straw Hats and the children are. Monet tells Caesar about Law having some relation to Luffy, which makes Caesar mistrust Law until Law reassures him. The Yeti Cool Brothers then attack the cave and shoot Brownbeard. They take Nami (Franky's body) with them. Luffy arrives and attempts to rescue Nami but fails. Law is challenged by two of Caesar's men as he leaves, and is forced to attack them.
Chopper tells the others that Nami in Franky was kidnapped by the Yeti Cool Brothers. Franky in Chopper takes a rumble ball and becomes unconscious, Luffy and Franky go after the Yeti Cool Brothers to save Nami and defeat them. Meanwhile, Caesar notices Vegapunk's beam in Franky's body and craves for it, he calls his men so they go to the fire side gate and see a cave. Luffy and the Yeti Cool Brothers fight and by the end Law appears and defeats them. Law then propsoses an alliance to take down a Yonko to survive in the New World.
Luffy and Law agree on an alliance; the rest of the Straw Hats disapprove while Robin approves, even if she warns Luffy about a possible betrayal in a pirate alliance. Law switches Nami , Franky and Chopper's bodies again. Nami ends up in Sanji's body because Sanji is far away with Zoro and Brook . Law tells them that they can't go back once things start moving for example capturing Caesar Clown who has the Logia type Gasu Gasu no Mi. He warns them that he is highly dangerous therefore, they need Haki users to beat him. Luffy says that the Haki users there are him, Law, Zoro and Sanji. The marines are continuing their fight against Caesar's men. The three centaurs open the door and see a big glop of Slime that seeps out poison gas, most of them die and two survive so they run as it chases them. Caesar calls the pet slime monster Smiley and says that the Straw Hats and the G-5 marines are being used as test subjects for it.
Zoro, Brook and Sanji are trying to find the samurai. Earlier they got knocked out by the Yeti Cool Brothers. Caesar's hazmat subordinates attack them but fail. They find the samurai's head frozen and unfroze him. They see Smiley far away. Smiley is a chemical experiment that caused the explosion in Punk Hazard. Law and Chopper are heading to the lab. Caesar drugged his test subjects to experiment on them. G-5 Marines attempt to break inside lab and then Luffy, Franky and Robin arrive out of nowhere surprising the Marines and Caesar's subordinates.
Luffy declares that he will capture Caesar. Law says he will deal with Monet while Chopper tries to find an antidote. Luffy and his group try to find the entrance to lab. Tashigi and Smoker attack Luffy, with Smoker gaining an advantage until Luffy uses Gear Second and tells Smoker to fight him later when he is at full strength. Back in the lab, the children start to wake up until Usopp puts them to sleep again. They then see pieces of Smiley falling onto the stolen warship. Franky, not being able to find an entrance, uses his Radical Beam to make an opening. The Marines try attacking it but discover that it emits poison gas when they touch it. One of them tries to burn it but it explodes when it catches on fire, destroying the ship. Back in the burning lands, Zoro, Sanji, Brook and The Samurai see Smiley shooting pieces of itself across the lake. Caesar then appears on top of the lab, explaining that Smiley was his experiment and that it is weak against water which is why it is shooting itself across the lake. After his speach, Luffy jumps up and grabs him.
Sanji, Kin'emon, Brook and Zoro see Smiley. Brook talks about a story about slime eating the clothes off of women making everyone act perverted except for Zoro, who points out that the slime is killing the fish in the lake, prompting Sanji to jump in to find Kin'emon's torso. Law tells Monet to take a walk with him while Chopper is left in the lab to find the antidote. Luffy faces off against Caesar who uses his Gas Robe attack until he discovers that Luffy is immune to poison. Caesar then uses his Gastanets and Smiley to injure Luffy who then grabs Caesar. Caesar then knocks Luffy out with an unknown ability. Robin, Franky, Tashigi and Smoker get knocked out as well. Law and Monet are walking down a hallway and encounter a mysterious figure who causes Law to break down in pain while the mysterious figure tells him that it's been a long time since they last met.
Law's heart is crushed by the mysterious man named Vergo who was sent along with Monet to watch over Caesar. Law gets knocked out by Vergo who had a bamboo stick with him imbued with Haki. Caesar tells his men to tie up the Straw Hats and G-5. Meanwhile Chopper is looking for a way to cure the children. Zoro's group are waiting for Sanji to rescue the samurai's torso. Sanji uses Haki to find the body and realizes it is in a shark's mouth. He manages to escape before the gas consumes him. The samurai then reveals himself as Kin'emon. He demonstrates his ability by cutting fire and by destroying the slime. He then attempts to find his son, Momonosuke. Zoro's group decides to aid him.
Vergo is still punishing Law and reveals that Vergo is the base commander of the G-5 Marine Base. On a unknown island inhabited by G-5 Marines that are extremely rude and take what they please. The citizens ask if they could look for their missing children. Revealing that the children in Ceaser Clown's laboratory were in fact kidnapped from this island. The Marines refused to help because they said Vergo looked over the missing reports and they all have died. Nami and Usopp who still are dealing with children who are going through severe withdrawals from not getting get any of their drug candy. Suddenly Caesar Clown appears and convinces the children to go back to the laboratory by bribing them with candy. Zorro's group are still dealing with Smiley and is furious that Kin'emon destroyed so much of the slime and decides to send huge slime attacks at them chasing them back to the laboratory. Luffy, Law, Robin, Franky, Tashigi, and Smoker in prison cell introduced to both Vergo and Monet. Meanwhile Caesar Clown's soldiers close all entrances to the laboratory leaving the G-5 Marines stranded outside to deal with Smiley. Vergo and Monet talk about what Caesar is planning but both are still quite not sure what he is planning. Smoker than calls out Vergo saying that his subordinates will die if he doesn't do anything. But, Vergo doesn't care less about what happens to them. Smoker pieces it together that Vergo is responsible for the cover-ups behind the missing children in the New World. Law then states that Vergo was never really loyal to the navy because he was originally a pirate all along working for the notorious underworld broker "Joker". Vergo then threatens both Tashigi and Smoker saying they will both die leaving his secret in tact. Luffy then asks Law "who is the Joker" and Law responds as someone that they all know who is a notorious pirate who works for the World Government. None other than, one of the Warlords Don Qiuxote Doflamingo.
As Luffy and Law remain captives in Caesar's lab along with the others who were captured, Caesar Clown goes to retrieve the children from the remaining Straw Hats.
Meanwhile, Zoro's group are still running from Smiley which has finally transferred itself to the ice lands, causing all of its pieces to converge together
The children tell Caesar that their heads hurt and he responded by telling them to go back to the biscuits room where there is more candy for them to eat. Mocha begins to regain her senses.
Vergo and Monet are waiting for Caesar. Caesar arrives and tells Vergo to keep Smoker in check. Vergo tells him its too hard to keep Smoker in check. It is revealed that Caesar made a deal with Law in the past to give his heart to him and in exchange he will get to keep Monet's. Caesar squishes Law's heart after Law gives a retort. Caesar is about to squish Smoker's heart when Monet stops him telling him that the broadcast is ready.
Caesar is about to give Smiley the big giant candy which is a weapon called Shinokuni. Zoro's group is still running away from Smiley. The dragon escapes from the sled and Caesar tells his subordinates to take off their suits and run to the lab. Smiley eats the giant candy and Chopper wonders what is happening while watching the broadcast
After Smiley swallows the oversized candy, the candy coat dissolves revealing a special drug designed to convert the entire content of Smiley's body into a "perfect" weapon of destruction, Shinokuni. In the process, Smiley dies and in a sack of apples, an apple turns into a Devil Fruit. The beast's body transforms into poison gas spreading quickly throughout the island. It's lethal power was demostrated when Caesar's men were caught in it, being petrified before the eyes of the Brokers and the captive Straw Hats. Zoro's team are seen desperately trying to outrun the approaching gas while Nami and Usopp help Brownbeard after their vicious attack by Caesar. At the Lab, Ceasar reveals to his captives that they will get to experience the poison gas as well, moving them outside dangling in a cave. In spite of their situation, Law told Luffy that their original plan will still carry on and that its time to strike back at Caesa
As the Underworld Brokers watched the video feed of the captive Straw Hats and Marines, Eustass Kid and Killer decided to ignore it for more important matters, such as forming an alliance between the Kid pirates, On Air Pirates and the Hawkins Pirates.
Law then decided to set his plan into motion and orders Franky to blow a fireball at a destroyed ship, creating enough smoke to block the cage from being seen from outside. Law then breaks free, explaining that he switched the sea prism stones with fakes during his stay on the island, and proceeds to free the others and restoring Tashigi and Smoker in their own bodies while securing their aid. Franky however had to leave them and protect the thousand Sunny. Meanwhile, Zoro and Nami's group are still running away from Shinokuni and they manage to join up while escaping. Luffy's group managed to enter the Lab with the aid of Law and they opened the gate, allowing the G-5 marines to get in before closing the gate, but the rest of the Straw Hats were still outside. Seeing their only chance of hope closing, Zoro and Kine'mon effortlessly cut the gate open, getting everyone inside safely.
Though the Straw Hats and Brownbeard managed to escape into the lab, they left behind a gaping hole. But they soon realise that Shinokuni can now enter the lab. The G-5 Marines panickly seals the hole back up with various wooden and metal planks. They succeeded in sealing the hole as Shinokuni proceeds to spread throughout the island. Brook uses the power of his Devil Fruit to become a soul and survey the area outside of the lab, noting that 'it was like the land of the dead'. After regaining their senses, the G-5 marines then turn their guns and swords towards the Straw Hats preparing to arrest them. Nami notices Law and demands him to switch back her's and Sanji's body, to which Sanji secretly refuses. Law agrees to return them to their original bodies and uses Shambles to switch their hearts back. Nami notices that she was wearing a different coat and punches Sanji, accusing him for peeping at her body. Law then explains to everyone present that they only have two hours to escape, he then continues by saying the only passage that leads safely leads out of the island is called R-66 and is found in Room R. The marines were reluctant, but quickly changes their mind when Smoker repeated the order to them. Smoker then orders Tashigi to take command of the men and rescue the children as he goes to confront Vergo. Meanwhile, Caesar Clown is celebrating the deaths of his victims but notices that the cage has no solidifed bodies, which he needed to prove the power of Shinokuni. He also notices the absence of the G-5 Marines. Vergo states that Luffy and the others must have broken out of the cage and helped the G-5 soldiers escape. Before Luffy went to fight Caesar again, Zoro calls out to Luffy reminding him that this is just the beginning of the New World and he mustn't let his guard down again, and Luffy happily complies as he plows through the Satyr soldiers. Caesar Clown then receives the news that the Straw Hats and Marines have broken into the Lab, leaving him alarm
Caesar Clown, incensed with the humiliation that his prisoners escaped and are inside his lab, orders the passage between building A and B to be closed and Shinokuni to be let in to kill the intruders. Vergo, however decided to take care of them himself. Chopper, who was eavesdropping snuck out and tries to find his way to the children within the labyrinth that is the lab. Luffy, Smoker and Law were the first to cross the gate before the alarm sounded, indicating the gate is beginning to close. Tashigi instead heard the alarm and quickly ordered the G-5 marines to let the Straw Hats go and hurry towards the closing gate. When a wall was blown up in building A, Shinokuni flows in petrifying some marines while the rest hasten their escape. The Straw Hats and most of the marines got through the gate safety but a few stayed behind to help Tashigi across before the gate closes, losing themselves to the poison gas while their captain watches in horror. Caesar, angered that they survived, promised that no one will escape this lab alive.
Though most of the G-5 Marines got through the gate safely, they were attacked by the small dragon who after a while flew away in fear. The marines cheered as their beloved Vice Admiral Vergo shows up but that turned to horror when he brutally assaulted them. Tashigi tries to defend them from him, but was viciously struck down. That action was enough to cause Sanji to come to the rescue, claiming he heard her tears falling. The Straw Hats (minus Sanji) and Brownbeard were still heading towards the end of the passage until the small dragon shows up and begins to attack them while Brownbeard suggests that he keeps running. Chopper manages to run into Mocha who was still hallucinating and manages to defeat the soldiers trying to apprehend her and give her a sedative to calm her down. Chopper then pleaded for her help to prevent the other children from eating the drugged candy. Meanwhile, Luffy and Smoker were racing towards building C where they believed Caesar and Vergo were located. They entered the private room where Caesar was angrily ordering Monet to release the poison gas on the marines only to turn around in shock of seeing Luffy fist buried in his stomach, who declared that he won't let Caesar escape again.
Luffy finally reaches Caesar's room and immediately punches the scientist, while Smoker leaves in order to find Vergo. Meanwhile, Sanji faces off Vergo while the passage between buildings A and B is closing and the previous one is opening, letting the poison gas enter. During the fight with Caesar, he tries to drain the oxygen in the area to kill Luffy, but fails once he enters Gear Second and use some attacks with Haki, making the scientist angry to the point of using some techniques as oxygen-made sword and fire bursts. Meanwhile, both Sanji and Vergo start running away from the gas. During this fight, Trafalgar Law makes his way to building D, where the SAD is made and Monet decides to enter the fight to protect Caesar, while he flies away, and reveals her snow abilities.
Law walks into the SAD Room. The door closes on Section A and it turns out Sanji is still alive. Tashigi tells the marines that the Vergo who attacked them is fake so that they could proceed with the mission. Vergo speaks with Doflamingo about Law while Baby 5 attacks him. Doflamingo stops her from attacking him. Monet shows off her powers to Luffy. Chopper keeps the drugged children busy so that Mocha can run off to stop the drug. The rest of the straw hats are busy escaping section B. Kin'emon and Brook cut down the dragon. A little girl tells the two hazmat suit guys that Momonosuke entered the secret room and turned into a dr
Chopper, in Monster Point, tries to hold the children for a while, however can't do it without harming them, so he eventually fails and returns to his normal form. Meanwhile, Luffy faces Monet off and almost dies in the battle, due to having his body frozen, but recovers and counters with Haki. The counter attack, however, made a hole in the floor, leading to the garbage room, where Luffy fell to, and Monet gives farewell to him, as "he can only escape flying". Trafalgar Law prepares to attack the SAD Room, but is confronted by Vergo, who gives critical punches with his Haki-powered fists and bamboo. In the biscuit room, Monet prevents Mocha from fleeing with the candy, and the Straw Hats also help Mocha. After almost killing Law, Vergo is confronted by Vice-Admiral Smoker, who prepares to fight the other Vice-Admira
Smoker and Vergo begin their fight in the SAD Room. At the same time, Sanji, Tashigi, and the G-5 Marines are running through the battle torn B-block when a gas tank explodes, causing Shinokuni to be let in. Caesar Clown, sitting on the second floor of R-block with his subordinates in Vegapunk's old room, instructs that the doors to C and D-blocks be closed, driving everyone to the first floor of R-block where a trap is ready to expose them to Shinokuni. When one of Caesar's subordinates questions the nature of the gas, Caesar then makes a speech to his subordinates, saying that the poisonous gas bomb four years ago was Vegapunk's doing and that Caesar tried to stop him. However, in a flashback it is revealed that Caesar constructed the weapon himself, and when he was told to stop and banished from the science squad, he set it off. While the gates to C and D-blocks are closed, Luffy meets a small dragon who can talk.
Luffy meets Momonosuke in the garbage dump of Block C. In a flashback, Momonosuke didn't want the candy Caesar gave out to the children and he got hungry so he ate a devil fruit which turned him into a dragon. Luffy and Momonosuke take off. Kinemon, Usopp and Brook look for sea stone handcuffs. Smoker continues his fight with Vergo. Nami, Robin, Zoro and Chopper are going after the children. Robin gets stabbed by Monet in the arm and Zoro defends the Straw Hats against Monet.
Mocha runs off with the candy and she thinks back in a flashback. Mocha and Sind are on a ship to escape from the poison gas. Mocha wants to go back home to her family, cries, and Sind tries to calm her down but he cries too. Caesar Clown finds them later and tells them that his own son died from the gas and he hoped to not see anymore children die from the poison gas. Mocha is still getting chased by the children who are drugged by the candy and she is making sure they don't get their hands on the candy. Monet introduced new children to the other children in a flashback. Zoro is fighting against Monet while Nami, Robin and Chopper are going after Mocha and the children. She uses her devil fruit powers to reach the three and Zoro blocks her attack from hitting Nami. Monet hopes to finish off the weaker Straw Hats because it is a strategic tactic. Monet blocks the entrance with a snow wall and is about to bite Nami on the arm until Robin prevents that from happening. Zoro opens up a pathway out of the room so that Nami, Robin and Chopper to get away from Monet. Luffy and Momonosuke is still getting out of the garbage chute until Momonosuke stopped and they both fell back down the chute. Caesar Clown is watching Monet fighting Zoro and the children chasing after Mocha. He talks about Shinokuni getting inside the facility being an important use. He says that they'll be killed soon. Usopp, Kinemon and Brook are getting chased by the poison gas and are trying to find the sea stone cuffs and Momonosuke. Monet asks Zoro why he is only blocking her attacks instead of attacking her. Sanji and the G-5 Marines arrived and Sanji sees Zoro and makes fun of him and the marines do the same. Sanji and the marines see Monet and are admired by her beauty. Monet uses her devil fruit powers and bites off a shoulder of a few marines causing them to panic. Sanji and the marines run off while Tashigi stays with Zoro to fend off Monet.
Mocha is still running away with the candy, and the kids are chasing her. Chopper, Nami, and Robin come to her and the children's aid. Then, G-5 and Sanji goes in their direction. At the Biscuit Room, Zoro and Tashigi battle Monet, with Monet almost breaking Tashigi's shoulder with her snow powers, but Zoro comes in and vertically splits Monet in half with a powerful One Sword Style technique. At the bottom of the C building, Luffy barely manages to hold onto a small ladge and begins to climb out, carrying an unconscious Momonosuke up the chute.
Mocha is running away with the candy so the children won't be able to get their hands on it and eat it. Chopper, Robin and Nami attempt to stop the children, but they eventually catch up to Mocha. She then eats all of the candy so that the other children won't be able to. Mocha wants to sacrifice herself for her friends. Zoro and Tashigi run away from the poison gas and are meeting up with the rest of the group. Chopper flashes back to when he and Mocha were discussing why the candy was bad to eat, while attempting to bar the door against the enraged children.
Luffy and Momonosuke manage to escape from the garbage chute. At the top, they are attacked by some of Caesar's sheep-men, but Luffy easily dispatches them using his Haoshoku Haki. Luffy leaves one of Caesar's men conscious, so that he can ask him where Caesar is.
Zoro carries Tashigi away from the poisonous gas. Sanji and the G-5 marines continue to assist Chopper, who is trying to get sedative injected into all the children. Usopp finds a door that leads to the room where Caesar and his subordinates are watching the Straw Hats and the Marines on a screen. Caesar notices Brownbeard on the screen, and confronts him. Brownbeard tells Caesar that he wants to get his crew back, but Caesar tells him they were all killed by the poison gas. Brownbeard tries to warn Caesar's subordinates, but Caesar drugs him to keep him quiet. Caesar orders his subordinates to get rid of Brownbeard, and they fire at him. Luffy arrives just in time and punches Caesar, before asking him about the island. Caesar tells him Punk Hazard is not supposed to exist, and nobody is supposed to know what happens on that island. Vergo covers up any information abut that island and anything that happens there - the SAD production is run by Donquixote Doflamingo, and SAD produces SMILE, an artificial Zoan Devil Fruit. One of the Yonko, Kaido, is forming an army of people who have eaten these artificial fruits. Caesar challenges Luffy to dare pick a fight with such people, only for Luffy to punch Caesar, and tell him that he has been picking fights all along.
Caesar tells Luffy to not underestimate Doflamingo, but Luffy keeps on attacking Caesar. Smoker continues his fight with Vergo. The Straw Hats, G-5 marines and the children run from the gas and continue to head towards building R-66. Caesar's subordinates find Usopp and attempt to attack him.
Vergo beats Smoker but Smoker manages to retrieve Law's heart and gives it back to him. Law tells Doflamingo he is going to defeat Vergo. Doflamingo tells Law to not underestimate Vergo because of his haki. Vergo imbues haki onto his whole body and attempts to kill Law but Law cuts him in half along with the SAD and the island. Law tells Doflamingo that he and the supernovas are going to be the leaders of the new era.
The kids stopped because they are tired and scared of running. Vergo attempts to kill Law even though he is cut down. The Straw Hats convinced the children to run and they continue to escape the poison gas. Caesar tells his subordinates to release the poison gas into building R-66. Caesar consumes the gas and becomes a big monster. He then consumes his subordinates to intimidate Luffy. Usopp tells Caesar's subordinates that Luffy will never betray his crew. Luffy defeats Caesar with Grizzly Magnum and sends him flying away.
Luffy defeats Caesar and sends him flying out of the facility. The Straw Hats, G-5, the children and Law made it to Building R-66 where they prepare to leave the building. Baby 5 and Buffalo spot Caesar and attempt to rescue him after contacting Doflamingo. Franky then spots the two from the deck of the SAD tanker.
Franky begins to attack the two Don Quixote pirates who retaliated with Baby 5 turning into weapons and Buffalo launching her at their robot foe. Caesar Clown regains consciousness and, after realizes his defeat remembers he still possess Smoker's heart and prepares to stab it. Inside Room R, the Straw Hats and everyone else are waiting for their comrades to return with Mocha before riding the transport cart out of the collapsing building. They managed to reach the group at the same time Usoop returned with Sea Stone handcuffs and the former subordinates of Caesar Clown. Momonosuke however was shockingly alarmed to see his father petrified.
Monet was moments away from activating the self destruct button when she felt her heart being stabbed and collapses before dying. At the same time Caesar Clown stabbed the heart believing it to be Smoker's heart. The Straw Hats are still racing towards the exit of the collapsing lab when they felt the explosion of the SAD room and then saw Shinokuni on their trail. Smoker, seeing that they nearly reached safety, questioned Trafalgar Law of why did he possessed his heart the whole time. Trafalgar Law reveals the clever deception he played on the mad scientist where he returned the heart of Monet to Caesar without Caesar being the wiser.
At the tanker, Baby 5's missile attack failed to take down Franky Shogun and their duel began anew whereas Buffalo contacted Doflamingo of the situation. After confirming that the island wasn't destroyed as intended, Doflamingo decided to tend to the matter himself and is seen somehow flying over the sea towards Punk Hazard.
Franky and his mech puts up a good fight against the two subordinates of Doflamingo and he sends them flying away with a portable version of the Thousand Sunny's Gaon Cannon, but the two refused to stay defeated despite their injuries.
The fight however was interrupted with the arrival of the mine cart filled with all of the lab escapees. Seeing that Law is allied with the enemy and that the odds are against them, the two decided to hightail out of Punk Hazard along with Caesar Clown in their possession. Before Law could stop them, Luffy told Law that Usopp and Nami will handle this. The two Straw Hats proved Luffy right as they easily stopped the fleeing pirates and succeeded in capturing Caesar.
Meanwhile, far away from Punk Hazard, Doflamingo is still flying toward Punk Hazard imagining what torture he would inflict on the brats, while elsewhere on a giant penguin, a mysterious man is wondering which direction leads to Punk Hazard.
The alliance of pirates and Marines prepares for a feast. Kin'emon and Momonosuke reunite at last. Nami complies to Tashigi's plea to let her take care of the children. Law explains who's really in charge.
Luffy learns about what the Yonko are capable of. The Marines and the pirates part ways. Doflamingo is blackmailed.
The Straw Hat Pirates, Kin'emon, Momonosuke, and Law are on course to Dressrosa. Doflamingo makes his move. A mysterious man appears on Punk Hazard.
Kuzan saves Smoker. Usopp and Chopper prepare for an attack. Kin'emon is mad with Zoro. Momonosuke tries to get attention from the girls.
A new foe appears. Caesar Clown gets kidnapped. The crew reunites with an old friend. Chopper goes berserk.
Breed reveals his plan. Luffy and Law go against each other. Dugong makes matters worse.
Chopper and the dugong make an attempt to go against Breed, but Breed orders the other animals to attack them. At that point Law, Caesar and Luffy enter the room and Luffy knocks the animals out. Law explains how he saw through Peto Peto no Mi's weakness, which requires the victim to actually hear Breed's voice in order to obey him. Breed uses his Devil Fruit to himself and manages to enhance his own strength and muscles and tries to attack Luffy and the others. However, his control over the other animals fades, which gives them the opportunity to work together and hold Breed still. Luffy and dugong throw a combined punch to Breed and manage to defeat him. Later on, on the Sunny, the news about Doflamingo's resignation arrive.