Synopsis / Summary / Plot
It's Christmas Eve in Avengers Tower and Shang-Chi is giving a bunch of youngsters a guided tour. They're talented kids who he's going to teach meditation and stuff at a retreat. But just now he's trying not to let individual Avengers' advice warp their young minds.
Tony Stark demonstrates how to make non-dangerous explosions, on the grounds that kids like to blow stuff up so they're better off knowing how to do it safely. Bruce Banner advises them to figure out what they're good at, but if they're not wealthy it might be a useless exercise. Black Widow recounts single-handedly killing 5 guys to show the value of improvisation, flexibility, hard work and training. Captain America tells them a team is only as strong as its weakest member.
One of the group, Zamira, is starstruck by Dr Banner. No-one notices that she's missing when Manifold teleports Shang-Chi and the youths to their destination.
The other 3 leave Steve Rogers to mind the store. Natasha has booked herself into a luxury hotel for some pampering. Banner is off to Geneva for a genetics conference. Tony is off to a private island in the sun. Before he goes Stark takes Cap for an update on the new security system. Steve isn't happy that his voice identification passcode has been updated from "Captain America" to "This is Captain Handsome ordering you to rock and roll on that 45".
When the room is empty Zamira comes out of hiding. But she's not alone for long as other versions of her start popping into existence. The 1st acts like her mother, followed by ones that seem like Cap and Tony.
Cap leaves the building to go to a shelter vwhere he's volunteered to help serve Xmas meals. The little old ladies in charge steer him towards a vet sitting alone, and they swap stories about the different wars. Then he returns to more humorous exchanges with the security system.
Meanwhile Zamira and her Stark-dupe are trying to break in to Tony's lab, whose passcode is simply "Tony Stark". This gets them in, but the alarms still go off and the door shuts again locking them in. Now that it has something real to report, the security system drops its funny side. As well as intruders in the Stark lab it reports life-forms in the personnel quarters and an unfinished men's washroom.
Cap races to the lab and hurls his shield at someone at the door. But it turns out to be Black Widow, who was actually 'vacationing' in her room in the Tower. Banner arrives too as the Hulk, claiming he didn't go to Geneva because the hotel lost his reservation. (These were the occupants of the personnel quarters.)
Hulk pulls the lab door off its hinges. Inside they find a chaos of Zamiras, now including versions of Widow, Hulk and Shang-Chi. The computer system is obeying the voice of the Tony Stark one.
Cap doesn't want Hulk raging in a room filled with Stark's machinerey, so he sends him to investigate the washroom. Steve rescues the real Zamira from a lecturing Shang-Chi (and from a robot arm), while Widow attacks her own duplicate. Both these dupes vanish in a puff of smoke. The 2 Avengers realise that the dupes are creations of Zamira. But their authentic-sounding voices are confusing the the Tower's computer system. And in response to an incorrect access code the system activates its laser defenses.
Meanwhile Hulk discovers that Tony Stark is in the unfinished washroom. His tropical desert island is inside there somehow. Tony is confused that the system is obeying orders he never gave. Then the computer detects his sunny island as a fire and releases a sea of foam on him and Hulk. (While they're being washed away Hulk admits that Banner didn't go to Geneva because he's broke - his funding fell through.) Iron Man suits up.
Steve and Natasha have gotten Zamira out of the laser-filled lab.But the girl can't stop generating duplicates. The Hulk and Iron Man dupes return, this time accompanied by a Thor. Iron Zamira accidentally hits on a command to unleash the cheerleaders - another of Tony's new defense systems, fembots dangling from giant balloons.
Cap and Widow are handling things when the real Iron Man arrives to defuse the situation. And Hulk deals with the balloon delivery system by biting holes in them. But now the Tower's self-destruct sequence has been activated. Stark can switch it off from his lab. But the lab's a wreck and he can't find what he's looking for.
Zamira blames herself for it all. But Natasha shakes her out of her self-pity and tells her heroes fix their own messes. Zamira creates loads of Avengers duplicates and gets them all to say "Cancel auto-destruct". Which amazingly works. But Tony's ego says he would have saved the day himself anyway.
Later Zamira gets the Avengers to pose for a souvenir photo with herself and her duplicates.