A disguised Captain America, Marvel Man, and the Vamp take a ferry to Alcatraz along with a group of tourists. Their mission is to locate the Falcon, who is a hostage of the sinister Corporation. Unbeknownst to Cap, there was a second traitor on the team of SHIELD Super-Agents: the Vamp….
Not far away, the Hulk and his pal Fred Sloan are driving along in Fred’s van (they met right before this in THE INCREDIBLE HULK #231) when they are stopped by the police. To Fred’s surprise and confusion, Hulk had fallen asleep and changed back into Bruce Banner (which Fred would know nothing about). The cops shoot Bruce and Fred with tranquilizer darts and the officers are revealed to be hired thugs working for Curtiss Jackson. They load the van and its sleeping passengers into a truck and drive off.
In the same general area, US Senator Eugene K. Stivak—who we know as Kligger, big shot in the Corporation—fakes his death in a plane crash with the help of his associate Dr. Karla (Moonstone) Sofen….
At Alcatraz, Cap and his allies separate themselves from the tour group and follow an energy tracer to an armored door. Marvel Man blasts it down—ruining any chance at surprise. They charge in and discover a large bank of computer equipment, a massive dynamo, and a canal between two large sea gates. To one of the gates, the unconscious form of the Falcon is chained.
Curtiss Jackson, West Coast Corporation leader, appears on a viewscreen and warns them that any hostile action will lead him to flood the chamber, drowning the Falcon. He tells Cap that the Corporation’s real interest is in the Falcon’s nephew Jim Wilson—and they also have another friend of Jim’s prisoner: Bruce Banner.
At this point Kligger and Moonstone arrive and offer to trade their hostage, Jim Wilson, for Captain America. He also reveals that the Vamp was a traitor…which causes Marvel Man to fly into a rage and attack, using a blast from his gauntlet to free Banner. Cap and Marv battle the guards while a terrified Banner changes into the Hulk.
Ol’ Greenskin confiscates the enemies’ guns and mashes them into a ball of scrap. Marvel Man tells the Hulk to fight Moonstone but the Hulk does not trust Marv (after meeting in DEFENDERS #62-63) and flattens him with a swat. Cap tries to calm Hulk down lest he destroy the building but Hulk only gets madder and tries to clobber Cap.
Jackson opens the other sea gate, flooding the chamber and threatening the Falcon; the surprise distracts Cap long enough for Hulk to get him in a bear hug and knock him out. Vamp pleads with Kligger for "the power" so he presses a button and she is transformed into the Animus; a combined attack by the Neanderthal creature and Moonstone defeat the Hulk, leaving all of the heroes helpless….
Story concludes in THE INCREDIBLE HULK #232.