Who will live? Who will die? Who will get diaper rash? Find out as the X-Babies face the A-Babies in the tie-in to end all tie-ins! Which side will crawl away victorious?
In the community of Marvelous Meadows and on the corner of Fury Drive and Xavier Way, Captain America's parents are putting him down for the night. Before nodding off, Cap wishes each of his bears a good night. Bucky Bear, however, is missing. He hears something outside and looks to find Cyclops holding Bucky Bear. Cyclops then dons his battle uniform. Cap follows suit and shouts into his baby monitor "Avengers Assemble!!!" and then springs into action. Iron Man, the Black Widow, Hawkeye, and Thor heed the call and baby Bruce Banner quickly tests the tension of his crib by turning into the Hulk. The Avengers meet Nick Fury outside, whose helicarrier is rising from the pool.
Cyclops, wanting to assemble the X-Men, sees a need for his own battle cry. Not having anything better, he yells out that he hears the ice cream truck. Tons of X-Men kids flock to the street. A battle soon commences between tons of Avengers and tons of X-Men. In the fray, Captain America and Cyclops battle over possession of Bucky Bear. Cyclops drops the animal and Cap lunges for it only to see Iceman whiz by and grab it. His ice bridge is broken, however, by Iron Man, who is thwarted by Magneto, who is thwarted by Thor. The bear is caught by Thor's hammer and crashes into a building. Wolverine is first on the scene and tries to lift Thor's hammer off the doll. He is miffed that he can't lift it. Hulk shows up and Wolverine takes a swipe at him. Hulk gets mad and hurls Wolverine into space. Hulk then cuddles with Bucky Bear until Mjolnir comes loose and knocks the Hulk and Bucky Bear back outside. The bear bounces around from fight to fight until it ends up back in the arms of Cyclops. Wolverine comes crashing back down to earth and warns everyone of an incoming threat. Everyone looks up to see Jean Grey bathed in the Phoenix. Cyclops still refuses to give the bear back since Cap is supposed to take it back himself. Jean uses the Phoenix Force to make everything right again. Captain America's parents find him in the morning snuggling with this Bucky Bear. They also see that the street and surrounding houses are in shambles.