Sougo Tokiwa seems like an ordinary high school student, but one thing he has different is that he has dreams of becoming a king! One day, a mysterious young man appeared before him with a prophecy. "Congratulations! Today is a special day for you..." As Sougo is told these words, a giant red robot suddenly appears before him! This robot was a time machine, and Sougo was thrust across various timelines! In the year 2000, the battle of the Heisei Rider's fate, and Sougo's fate in his own birth year, is about to begin...!
Sougo is attacked by a Kamen Rider from the future, Geiz Myokoin, but is saved by a girl from the same future Tsukuyomi, who wishes to help him out. With no clear idea of what is going on, his confusions are further pushed with frequent visits from the mysterious prophet named Woz. Meanwhile Another Build is wreaking havoc, and Sougo discovers that the key to defeating this "Kamen Rider Build" is to meet Sento Kiryu.
Geiz and Tsukuyomi reluctantly collaborate with Sougo, even going as far as to keeping a keen eye on him at school. Meanwhile, a seemingly "unbeatable" game has gone viral amongst the students at Sougo's school, with rumors saying that there is only one person who would be capable of beating it. The three set out to find this rumored genius gamer M, but they encounter an enemy Time Jacker named Ora.
Sougo and the others find Emu Hojo, also known as Kamen Rider Ex-Aid and engage in battle with him. However with the appearance of Another Ex-Aid, Emu memories and powers are stripped from him. Despite so, Sougo needs to somehow gain Emu's trust in order to gain the Ex-Aid Ridewatch and defeat Another Ex-Aid.
Geiz and Tsukuyomi investigate a case of young girls mysteriously disappearing from Amanogawa High School, and are confident that an Another Rider is involved. When their suspicions are proven true, they receive a handful of support from the school's Kamen Rider Club .
With Another Fourze also possessing the powers of Another Faiz, Takumi Inui appears to stop Masato Kusaka and help Sougo investigate the case. As they continue searching for answers behind the mystery of Another Fourze/Faiz's target Karin Yamabuki, they discover a connection with the Ryusei School.
Sougo and the others attend a magic show that was rumored to use real magic instead of just sleight-of-hand tricks, powers that Geiz believes is associated with Kamen Rider Wizard and believe it to be the works of an Another Wizard. Just when Geiz attempts to question the magician, Sougo is...
Tsukuyomi has fallen into a coma thanks to the magic spell that Another Wizard used on her! Geiz, who was wary of Hayase (Another Wizard) since the beginning, tells Sougo off that his kind of approach is what caused Tsukuyomi's coma, as he goes off to save her himself. Just then, Kosuke Nitoh suddenly appears before him...! Meanwhile, Sougo tries to find the meaning behind Woz's mysterious words...
In the news, the Dan Foundation had declared its independence from the nation of Japan, with its CEO Kuroto Dan proclaiming himself to be a king. Sougo's curiosity with this man leads to the discovery of Kuruto's identity as Another OOO, and Geiz goes back in time to destroy Another Rider at it's source, but Sougo takes a different course of action...
Hina and Eiji were both suddenly captured by King Kuroto Dan! While working together with Hina, Eiji tries to help them escape, which Sougo is trying to prevent! Why is Sougo doing all this? And what is the future that Eiji told him about? Geiz, on the other hand, is more confident now than ever before that Sougo is on the path to become the future's demonic king...
Zi-O fighting... with GaimArmor?! Woz begins his celebration, however, when did Sougo acquire the Gaim Ridewatch? Time proceeds as normal. There are suddenly reports of popular dance team members disappearing one after another. Sougo comes to terms with the fact that Another Rider must be behind these sudden disappearances. However, Sougo seems to be acting somewhat different than usual...
Why are there two Sougos?! Sougo is getting scolded constantly by both Tsukuyomi and Woz. Meanwhile, they start to discover that this other Sougo came from a little farther in the future to travel back in time in order to help Geiz! Being vehemently opposed to Sougo's attempts to rescue Geiz, Woz makes his way towards Sworz's lair...
Geiz was able to return home from Helheim successfully, only now he has a renewed determination to kill Sougo at any time, and anywhere! Another Rider suddenly appears in the city, to be striking people down and taking their souls away! Takeru Tenkuji and Narita of the Mysterious Phenomenon Institute set out to capture this Another Rider, but as soon as they reach the location, they see none other than... Kamen Rider Agito?!
Sougo has become a ghost! His spirit is invisible to both Tsukuyomi and Geiz! In order to return Sougo back to normal, Geiz travels back to the year 2015! Geiz encounters and starts to fight Another Ghost in 2015, but just then, Kamen Rider Decade appears!
Why does Sougo want to become a king in the first place? Sougo starts to tell Tsukuyomi about the continuous dreams he's been having. Just then, a giant event, just like the one in Sougo's dream, suddenly starts to manifest! A giant mecha suddenly appears in the sky! The demonic king's servant from the future, Kasshin suddenly appears! And thanks to Decade's intervention during their fight, Sougo gets blown 50 years into the future...!
"If you throw away that belt, then you'll never become the demonic king... You can change the future..." Sougo after hearing the words of Ohma Zi-O was faced with an excruciating decision. Strangely the DaiMajin that exists to destroy the world still exists. After witnessing the crisis that Geiz is facing, Sougo makes his decision. What will Sougo choose to do?!
It was Sougo himself who ultimately made the decision to continue fighting as Kamen Rider Zi-O! However, his choice came at a cost, as the flow of time has suddenly been changed! Suddenly appearing before Sougo and the others appears Another Shinobi, who was created from the abilities of Kamen Rider Shinobi, who shouldn't even exist in this timeline's history! Also, another mysterious Woz appears before Sougo and the others and stands before the present Woz...!
Another Woz has appeared and just transformed into a Kamen Rider! Why did he come here from another future, the future where Ohma Zi-O disappeared? Furthermore, in order to destroy Another Shinobi, the Shinobi Miridewatch is required, however, because Kamen Rider Shinobi exists in "another future" it is not possible to encounter him. Just then, Sougo notes that Rentaro was once a Kamen Rider...
A new unknown Another Rider suddenly appears! The Black Woz approaches Sougo, while the White Woz approaches Geiz, each one of them is determined to have their Rider deprive the other of their powers in order to lead them towards their own desired future! Furthermore, a new warrior from the future, Kamen Rider Quiz suddenly appears!
Kamen Rider Quiz suddenly appears direct from the year 2040! In order to make Geiz the savior of the future, and deprive Kamen Rider Quiz of his powers, White Woz starts a fight between Zi-O and Geiz! Father and son, arriving to the year 2019, Quiz faces his own father, Another Quiz in battle! And still, this raises yet another problem...
An incident arises when a new Another Rider starts terrorizing the city! Despite Sougo and Geiz working to fight against this creature, whatever attacks they launch against it are reflected back with twice the power, as the Another Rider escapes! Sougo, who discovers that these incidents are related to ORE Journal makes his way towards a fishing pond. While there, Sougo finds a man named Daisuke Okubo, who suddenly drops the name "Shinji Kido"...
Sougo is trapped in the Mirror World where he encounters a reversed Zi-O! Reverse Zi-O begins to tell him "You are a hypocrite! You are the one who will become the most despicable and tyrannical demonic king!" Is the man in the mirror Sougo or Shinji, are they the real versions of themselves? Furthermore, Geiz decides to use a deadly move to destroy Another Ryuga forever!
Sougo is at risk of being unable to graduate unless he passes his final examination! Sougo starts to focus and study hard but he dozes off and starts to dream again. In his dream he sees a future where humans and machines confront each other, as well as Kamen Rider Kikai!
In order to access the powers of Kamen Rider Kikai, Sworz uses Heure as a catalyst, forcing him to become Another Kikai! White Woz attempts to strip them of that power so he can grant it to Geiz to make him even more powerful. Meanwhile, Time Jacker Ora has a lot on her mind, as she makes her way to 9 5 DO with some suggestions. Furthermore, Rento is busy rampaging around the year 2121! Sougo decides to work together with the local children to find a way to stop him, but...
The defeated Another Riders begin reappearing and attack the people who they manifested from their contracts with the Time Jackers. Sougo investigates, but encounters a new enemy in the form of a vaguely familiar face who is masterminding the Another Riders' attacks and can transform into Another Rider with similar powers to Zi-O.
Tsukuyomi travels to the past to discover the connection between Sougo and Another Zi-O, while Geiz decides to finally put the new power he gained from White Woz to use.
Geiz reaffirms his intention to stop Sougo from becoming Oma Zi-O, but Woz allies himself with Heure to intervene in the fight between the two Kamen Riders.
Hiryū and Black Woz, as Kamen Rider Woz, confront Sougo and Geiz, respectively. The two riders however, are determined to overcome all obstacles and confront each other in their destined fight.
Sougo has finally made peace with Geiz and Tsukuyomi, but they have little time to celebrate as a new Another Rider, as well as other Kamen Riders from the past, appear before them.
With the forced battle between Kamen Riders Blade and Chalice threatening all life on Earth, White Woz appears before Geiz with the Zi-O II Ridewatch, the Geiz Revive Ridewatch, and a solution to this crisis.
Sougo has collected fourteen Ridewatches thus far. In order to become the demonic king of time, he must collect the remaining six. Meanwhile, the police special forces, G3 Units are seen fighting against Another Agito! Sougo decides to aid them in their fight, but suddenly the Another Agito's begin to multiply! Sougo decides to try and find the original Kamen Rider Agito, so he makes his way towards a restaurant known as AGITO...
The Another Agito attack incident breaks out after the G3 System is preparing itself for battle! After planning to meet up with Kamen Rider Agito himself, Sougo and the others finally come face to face with Shouichi Tsugami! But what quickly appeared there was a Time Jacker! They're using the power of Kamen Rider Agito to create an Agito Ridewatch, of which they embed within the body of Another Agito! Sougo begins to struggle against the threat of a strengthened Another Agito. In the midst of battle, Tsukuyomi uncovers a secret power hidden deep within herself, when just then Shouichi appears...
Woz struggles to figure out how to properly celebrate Sougo's upcoming birthday as Another Hibiki attacks with Todoroki and the current holder of the Hibiki title dealing with the Another Rider themselves.
As Sougo's birthday arrives, he appproaches Kiriya Kyousosuke for Kamen Rider Hibiki's powers, but the latter reveals that he had never truly surpassed his teacher.
A lawyer visiting Kujigojidō is attacked by Another Kiva, Sougo's childhood crush who seeks to become "queen" of the world. Just then, an new enemy named Kamen Rider Ginga enters the fray to destroy the world.
Finally aware of who Another Kiva is, Sougo approaches her in an attempt to make amends just as the Time Jackers try to form an alliance with her to stop Kamen Rider Ginga. Meanwhile, Geiz travels to the year 2015 to find out what really happened to Sougo's first love.
Meteorites starting falling all over the city, and release Worms that start attacking; with Another Kabuto and the Hopper Brothers apparently leading them. To combat them, the Time Riders have to locate Kamen Rider Gatack just as Tsukasa returns with the revelation that Tsukuyomi has had something to do with this crisis.
After destroying the meteorite, the Time Riders learn that an even larger one is on the way with Sougo and Woz attempting to destroy it despite Another Kabuto's attempts to stop them. Meanwhile, Tsukasa leads Tsukuyomi to a strange house so she can learn a shocking truth.
As Kujigojidō receives a surprise visit from the Taros Imagin when they need Junichirō Tokiwa to repair the DenLiner, the Time Riders find themselves dealing with Kamen Rider Zeronos and a new Another Den-O.
Though Sougo acquired the Grand Zi-O Ridewatch, it disappeared as the result of Yuto's meddling with the timeline. The Time Riders realize that Another Den-O made a contract with the Mole Imagin as they and the DenLiner crew join forces to reclaim the stolen DenLiner from Another Den-O while Sougo ends up having another encounter with Oma Zi-O.
Sougo and Oma Zi-O have their climatic rematch when a temporal distortion returns the former to 2019. There, Sougo finds his timeline has been greatly altered with his granduncle not knowing who he is, Geiz and Tsukuyomi seeing him as their enemy again, and Woz now serving Hiryu who has took over Oma Zi-O's place as the tyrant king as the Another Rider Another Zi-O II
Geiz attacks Sougo, even in spite of the latter's refusal to fight his friend. Just then, Tsukasa returns to seemingly aid them. Meanwhile, Daiki Kaito approaches Hiryū and Woz to claim their "treasure"
With Tsukuyomi captured, Schwarz begins to reveal the story behind her amnesia as well as his plan, which sends Heure and Ora running; forcing them to seek out the Time Riders as they and Tsukasa join forces to confront Another Zi-O II and his army of Another Riders in a epic showdown.
As the Time Riders investigate the disappearance of a former classmate of Sougo's, they encounter Michal Minato/Kamen Rider Aqua, who has come from 2050 to take Tsukuyomi and Geiz back to their time for unknown reasons. However, while fighting Another Drive, the group are confronted by Swartz, who reveals his new power as Another Decade while he's gathering the Another Riders' power for himself.
With Another Drive's identity supposedly revealed, Geiz argues with Sougo over both trusting Heure and Ora while questioning if he has any right to remain in the present. Meanwhile, Swartz recruits Kamen Rider Eternal to his side after spiriting Sougo's classmate Kowada away.
Geiz becomes trapped in Swartz's Another World, with a revived White Woz taking his place to confront Black Woz. Meanwhile, Swartz's plan nears completion, but Michal Minato stands against him with the last of the courage that Kamen Rider OOO gave him.
Strange occurences happen all over Japan, from a strange wall dividing the country to Sougo's Ridewatches mysteriously losing their power. With Tsukasa's powers, Tsukuyomi takes Sougo to her original timeline to investigate as an army of Roidmudes led by Mashin Chaser stand in their way.
As Earth is subjected to a mass convergence with the A.R. Worlds and his friends continue to fight Swartz and the influx of past monsters, Sougo realizes he is the epicenter of the chaos and travels to 2068 to settle things with Oma Zi-O in a final confrontation.
Tsukuyomi has became a Kamen Rider, only to betray everyone and advance the A.R World apocalypse. After Geiz is killed attempting to stop Tsukuyomi, a disturbingly calm Sougo resolves to end Schwartz's scheme and stop his former friend by becoming Oma Zi-O as the final battle reaches its conclusion.