Janet Van Dyne waits impatiently as Henry Pym completes his latest research task. They are extremely late to a black tie fundraiser and lecture by noted geneticist Moira McTaggert. While Hank busies himself getting ready, the couple begins to argue about Jan’s activities in the Avengers, activities Hank is just now discovering.
At the Black Tie gala, Tony Stark and his date Pepper Potts, meet Professor Charles Xavier, himself a world-renowned geneticist and expert on mutation. Xavier is accompanied by two of the graduate assistants from his school for gifted youngsters, Scott Summers, and Jean Grey, as well as one of his youngest students, Kitty Pryde. Pryde charms Tony with her excessive knowledge of his Arc reactor technology, and Stark agrees to arrange a tour for her of Stark Tower.
Pepper leaves to get the pair another drink, and Tony is confronted by Simon Williams, whose Williams Industries has just been purchased by Stark Solutions. Williams begs Stark for assurance that none of his staff will be fired, and Stark gives his word of honor.
In Central Park, Thor escorts Jane Foster on a late night walk. Foster attempts to explain the concept of “muggers” to the Odinson, finally settling on “brigands”, a term that only invites Thor to welcome battle. Jane informs Thor that she will be missing the press conference officially announcing the Avengers to the world, as she will be In New Hampshire with her mentor, Doctor Erik Selvig, working on a new state of the art observatory. Their walk is interrupted by a disturbance in the trees nearby, which turns out to be not brigands, but a fully-grown Tyrannosaurus Rex!
In the Sanctum Sanctorum, Doctor Strange is beginning the Scarlet Witch’s arcane training. As Strange’s manservant Wong looks on, they begin with deep meditation, attempting to teach the Witch to control the chaos forces at her control. They receive an Avengers emergency call informing them that Sentinels have appeared in Times Square and are attacking everyone visible in their hunt for mutants.
Janet and Hank’s discussion is similarly interrupted, by the appearance of World War One biplanes dogfighting over the campus of Empire State University. Hank transforms into Giant-Man and pursues the planes, but Janet is distracted from screams from the student quad, where she finds a giant, insectoid alien attacking anyone it sees!
Back at the gala, Tony Stark is approached by Whitney Frost, who offers to purchase Williams Industries on behalf of Roxxon Energy. When Stark refuses, Frost makes a different proposition, one that involves Tony spending the night with her. Pepper, observing this interaction, becomes furious with Tony and storms out of the party. Tony’s pursuit is interrupted by a call from Stark Tower. A mysterious individual informs Stark that if he does not go to the tower immediately, a group of hostages will be executed. Donning his armor, Tony regretfully sends his chauffer and body-man, Happy Hogan, after Pepper, and makes his way to Stark Tower, where he is met by a stranger who identifies himself as Kang the Conquerer.
Kang informs Stark that he has travelled from the 42nd century to execute Stark before Stark can unleash the Singularity, a self-aware artificial intelligence that will eventually destroy the world. It is Kang’s arrival in the present that has caused the chronal rifts causing the other avengers’ current predicaments. Refusing to simply lay down and die on Kang’s say-so, Iron Man engages the stranger in battle.
The Avengers take on their time-displaced foes while coordinating via their Identicards. Strange manages to subdue both Sentinels by encasing them in icy prisons. He teleports The Witch to Stark Tower to aid Iron Man. Simultaneously, he issues a telepathic summons to ‘call in a favor”. That favor turns out to be Luke Cage, the Hero for Hire, who appears on the ESU campus and aids the Wasp in defeating the alien predator. At the same time, Giant-Man manages to scoop the bi-planes from the air.
Thor bests the Tyrannosaurus, and bridles it, claiming the beast as his mount. The Avengers converge on Stark Tower, where Kang has battered Iron Man almost to death, and has temporarily depowered the Scarlet Witch with a 42nd Century weapon. The combined might of the heroes proves ineffective against Kang, as the madman transports them into the ruined wasteland of his future. There, he manages to finally defeat Iron Man and prepares to kill him.
The Avengers blink, and are surprised to find Iron Man still alive. Kang angrily informs them that he just executed Stark, but nothing in his future changed, leading him to determine that his calculations where wrong and Stark was not the cause of the Singularity. He then snatched Stark from the instant immediately before he was killed, effectively resurrecting him.
Swearing that he will restore his future even if he must conquer our present, Kang returns the Avengers to present day.
Iron Man offers Giant-Man membership in the Avengers, but Pym declines, saying that he respects what the team is doing, but believes he can be of more use to the world as a scientist than as a super-hero.