The Legion Corps are ordered by Zentopia's archbishop to retrieve the missing pieces of the Infinity Clock and seal them again. Before leaving on their new mission, they visit Fairy Tail and make amends with the guild for attacking them. Natsu and his friends later learn that Fairy Tail has lost their title as the strongest guild in Fiore to Sabertooth, which rose to power over the seven years they were frozen in time. Two of the strongest wizards in the guild include a pair of Dragon Slayers named Sting and Rogue, who are obsessed with fighting Natsu and Gajeel, respectively. Meanwhile, Makarov brings Gildarts to their abandoned guildhall and shows him Lumen Histoire, a light that Makarov says is Fairy Tail's greatest secret. Makarov then tells Gildarts that he has been chosen to become the next master of Fairy Tail.
Natsu and his friends who returned from Tenrou Island learn that the rest of their guildmates have surpassed them in magic power. They visit Poluchka for medicine to strengthen their magic, but are turned down. Wendy recognizes Porlyusica's voice and scent as those of Grandine, the dragon who raised her. After apologizing to the group, it is revealed that Poluchka is the Grandine from Edolas who is now stuck in Earthland. Following directions from Grandine, Poluchka gives Wendy written instructions for two advanced spells the dragon failed to teach her. Meanwhile, Makarov announces Gildarts' succession as master to the rest of the guild, only to find he has gone on a journey, leaving a letter of resignation behind. In the letter, Gildarts reinstates Laxus into the guild, returns mastership to Makarov, and tells him to make Fairy Tail the strongest guild in Fiore again. Romeo suggests they participate in the Grand Magic Games, an annual festival designed to determine the guilds' rankings. Despite the rest of the guilds' objections after suffering six consecutive losses in the games, Natsu and his friends eagerly accept.
With the Grand Magic Games occurring in three months time, Lucy and her friends go to a seaside resort to begin their training section. On their second day of training, Virgo appears and tells the wizards that the Celestial Spirit World is in danger of destruction. When the wizards arrive, they instead find a surprise party held by the Celestial Spirit King celebrating their return from Tenrou Island after seven years. They spend a day partying with the spirits, only to realize Virgo before they leave that one day in the spirit world equals three months in the human world.
While mulling over their lost training time, the Fairy Tail members receive a message via carrier pigeon requesting a private meeting in the forest nearby. There they meet a runaway Jellal, Ultear, and Meldy, who have formed their own guild, Crime Sorciere, to defeat Zeref and any dark guilds that try to use his power. The three ask Fairy Tail for their help in determining the source of a magical anomaly similar to Zeref's magic that they have sensed around the Grand Magic Games arena Domus Flau. In exchange, Ultear uses her magic to double their magic power. As the others undergo the painful "power-up" process, Erza talks with Jellal over his regained memories. The two nearly kiss, but Jellal decides he and Erza cannot be together and lies to her that he has a fiancée. Erza quickly picks up on this and respects his decision, seeing Crime Sorciere off as they leave.
Natsu, Lucy, Gray, Erza, and Wendy are chosen to represent their guild in the Grand Magic Games, which are to be held in Fiore's capital Crocus. As they tour the city, Natsu and his friends meet Sting and Rogue, who mock Natsu for not being able to kill Acnologia and boast killing the dragons who raised them. At midnight that night, Fairy Tail and the other participating guilds are put through a preliminary event—a race through a massive floating labyrinth—designed to narrow the guilds down to eight teams.
In the elimination round, Natsu and the others have to make their way through the Sky Labyrinth, a giant mind-bending maze full of rotating walls and vicious rivals!
The eight participating guilds of the Grand Magic Games are introduced! Along with Fairy Tail, there are old friends and rivals, old and new enemies... and at least one team that's completely unexpected!
It's "Hidden", the opening game of the Grand Magic Games, and Gray finds that it's like playing cat and mouse. Unfortunately, he's the "mouse" as he keeps getting picked off by a member of Raven Tail!
In the first battle of the first day of the Magic Games, Lucy is pitted against Raven Tail's Flare, whose long locks are deadly. But when Flare doesn't play fair, Lucy is forced to grin and bear it or risk a friend getting hurt!
There are more one-on-one battles on the first day of the Grand Magic Games, culminating with the mysterious "Mystogan" versus Jura! Will a Fairy Tail team finally get points?! Or will Mystogan's real identity be revealed, blowing his secret mission?!
The second day begins with a chariot race of a sort, obviously not the best event for Natsu as his motion sickness kicks in right away! Surprisingly, though, he's not alone as two more participants suffer from the same affliction!
The battle portions of the second day continue with Kurohebi defeating Toby Horhorta and then showing his crueller side by ripping Toby's prized sock. Whilst everyone is watching the Games, malicious activities seem to be happening in the background, with Wendy, Porlyusica and Carla almost being kidnapped! In the midst of this chaos, an error by Arcadios sees Elfman fighting Bacchus. Does Elfman have what it takes to win, or is the outcome of this match already set in stone??
Instead of duking it out for their match, former pinup models Mirajane and Jenny go head to head in a crowd-pleasing swimsuit pageant. But things get out of hand when all the wizard women join in!
The last battle of the second day pits Kagura, Mermaid Heel's strongest wizard against Yukino, a young Celestial Spirit Wizard on Sabertooth's side. They bet with their lives and Yukino threatens to make good on it when she opens the unknown 13th Gate!
After being drummed out of Sabertooth, why does Yukino pay Fairy Tail a visit? And what is Erza going to do when she learns that two more people want to murder Jellal, including a dear friend?!
Confronted by the Sabertooth Guild Master himself, Jiemma, Natsu decides to fight him all-out in their lodgings. Despite his attacks, he is unable to deal even a scratch on him. Eventually, their "fight" is interrupted with the arrival of Minerva and her hostage, Happy, forcing Natsu to leave reluctantly. The following day, the Grand Magic Games resume with a new event: Pandemonium. However, the beasts within the domain of this event appear to be quite challenging for the participants.
In the event called Pandemonium, Erza has opted to take on 100 powerful magic-generated monsters by herself... but what is the secret of the one S-class monster?!
The third day of the Grand Magic Games proceeds into the battle portions. The first match, Mermaid Heel's Millianna and Quatro Puppy's Semmes, results in an unexpected win. Rufus Lohr easily dominates Eve Tearm in the following match. Then, in the next match between the father-and-son Guilds, an unexpected play from Raven Tail seemingly gives them an incredible advantage against even Laxus Dreyar.
Laxus takes on Raven Tail's elite, but they're after something more than a win! And then there's Wendy vs. Cheria, a battle royale between two masters of the wind!
The match between Wendy Marvell and Chelia Blendy continues, with Chelia using her ultimate move. Elsewhere, Jellal watches the match, noting the dark magic. However, as the battle ends, he realizes that the evil aura is coming from someone else. As he tries to chase the mysterious person, he is quickly intercepted by Doranbolt and Lahar. Will Jellal be able to escape? And what is the result of Wendy's battle?
As Fairy Tail happily parties in a bar to celebrate their earlier victories, others all around Crocus contemplate the harsh realities of things they have witnessed on the third day, and those to come. Malice also lurks in Sabertooth, as, in the Naval Battle event the following day, Minerva succeeds in brutally attacking Lucy as a demonstration of her guilds power.
Whilst Lucy is in the infirmary due to Minerva's cruel play in the Naval Battle event, Fairy Tail Team A and B are forced to merge to even out the odd number of teams. With tension building between Sabertooth and Fairy Tail, the tag battles begin with Team Blue Pegasus against Team Quatro Puppy, the man in the blue bunny suit finally revealing his identity.
The fourth day of the X791 Grand Magic Games continue with the second match of the day, Lamia Scale against Mermaid Heel. Both sides struggle to win, only to end the battle in a draw, leading to the beginning of the last match between Fairy Tail's and Sabertooth's Dragon Slayers.
The fourth day's final battle between Sabertooth and Fairy Tail kicks off with Natsu and Gajeel proving themselves as formidable opponents against the Twin Dragons of Sabertooth, but when push comes to shove, Sting and Rogue decide to utilize their trump card and turn the tides of the battle. Will the Fairies attain victory against their opponents or will the Tigers stay true to their title as Fiore's strongest guild?
The tag battle of the Dragon Slayers comes to a close, with Natsu intrepidly overpowering the combined attacks of Sting and Rogue. The Sabertooth members watch in dismay, whilst Jiemma seethes in anger over the defeat of the Twin Dragons, causing the nearby spectators to be frightened away. On the contrary, the rest of Fairy Tail celebrates in joy as its team receives 10 points, finally surpassing Team Sabertooth by only a single point. Meanwhile, Gajeel, back to his senses after being dragged by Natsu into a cart earlier, stumbles upon a cave full of dragon skeletons, much to his shock. And during that night, Jellal finally manages to corner the source of the dark aura, standing in complete disbelief at the identity of the mysterious, hooded person.