The students have been "grounded" ever since their excursion in the previous films. This has sat none too well with any of them. However, they have had time to grow in their powers and, in some cases, relationships. Quentin and Idie are awkwardly attracted to each other despite their violently clashing personalities. Alex continues to pine for Polaris, despite knowing she is the daughter of Xavier's old rival Magneto.
Meanwhile, the X-Men discover that a forces tied to a mysterious have been kidnapping mutants across the world. Professor Xavier seems oddly reluctant to engage, and argues with Scott over the mission. Against his mentor's advice, Scott leads the team into action. They are quickly caught off guard upon arrival, for the resort is in fact built upon Krakoa, the living island. The entire team is captured and introduced to the resort's owner: the eccentric Arcade, who has constructed a massive playground for the world's most amoral billionaires, centered around "Murder World", his own modern gladiatorial arena. The star contestant: the mysterios, beserk fighter The Wolverine.
In the mansion, the team's failure to report back causes alarm. Xavier and the school staff spar over how to respond, and the professor shuts himself off from the school. Taking matters into their own hands, Beast and Forge opt to send the students in to discover what is going on, a task they are all too eager to accept. Beast's tech allows them to circumvent the island's defenses.
In the arena, the X-Men are forced to face down The Wolverine. Together, they seemingly defeat what appears to be a crazed monster, but only after suffering many severe injuries. The fight ends when Jean, Storm and Scott unleash the full force of their power to take down their foe. Arcade is exubriant at the thought of new champions far more "aesthetically pleasing" than his old one. The leaders of the X-Men, however, are decidedly not on board with his game, and are sent away for "re-education". Wolverine's "body", meanwhile, is taken away, only for him to break free from the compound upon his recovery.
Back outside, the rescue team is divided on the best approach. Beast attempts to charm his way into the resort, but it ends with he, Anole, Mercury, and Gentle being dragged off to Arcade's labs. Only Havoc is able to slip in unnoticed. Forge, Quentin, Armor and Oya remain behind to guard the ship, but are confronted by Wolverine, looking for a way off the island. After a tense standoff, Wolverine agrees to help them take down Arcade's schemes. He reveals he remembers nothing of his past, only a name, Logan, and that he is far older than he looks.
Inside the resort, Havoc continues to blend in and investigate the inner workings of the island. He is caught off guard, however, by the sudden arrival of Polaris, in disguise alongside her father Magneto and the highest ranking members of The Brotherhood: Pyro, Destiny and Post. Magneto claims that they were contacted and directed to the island by Xavier himself. Havoc agrees to work with them, helping Post to hack into the resort's server, giving them a view of the insane expiraments taking place in the islands labs.
Beast and Anole are getting first hand looks at these expiraments. Miss Corriander unveils the latest creation: Predator X, genetically modified beasts spliced with DNA from captured mutants, including the X-Men that had been taken away for "medical treatment".
Quentin and Destiny develop a telepathic rapport to coordinate their assault on the resort. An epic battle breaks out as our heroes fight their way through Arcade's security and elaborate death trap defenses. The Predator X's are released, but are defeated by the combined forces of the X-Men and the Brotherhood. The Brotherhood and Havoc reach Arcade's control room. Polaris mercy-kills the telepath Aracde was using to control Krakoa and Destiny takes over, defeating Quentin in a psychic duel. Miss Corriander betrays Arcade, leaving him to die.
With Magneto now in control of Krakoa, the X-Men are allowed to leave, along with Wolverine. Havoc, however, chooses to remain with Polaris and the Brotherhood, a decision that leaves Scott distraught. They return to the mansion with the student's standing greatly increased, as Beast declares them "true X-Men". The elder mutants relationship with Xavier, however, is seriously strained, as it becomes clear he has been keeping secrets from them.
POST CREDITS
-Magneto leads Havoc to the heart of Krakoa, promising a reveal of Xavier's oldest secret. There lies the comatose Gabriel Summers: Vulcan.
-Logan adjusts to life in the X-Mansion and is confronted by Armor, who wants him to teach her how to fight like him.
