As Captain America walks alongside a river, seeking escape from Rio de Muerte, he is suddenly attacked by a fishlike monster. Guards working for the Latin American dictator Hector "The Swine" Santiago arrive and drive the Man-Fish off with their gunfire and take the wounded Cap prisoner….
Back in the States, SHIELD is worried about Cap and the Falcon, since their help is needed with File 116, a giant insect-man on the loose. Leila drops by and appeals to the agents to find Cap and the Falcon. The Falcon, meanwhile, on his way to Rio de Muerte spots a giant nest and lands to investigate….
Down south, Cap fights back against the guards in a whirlwind of action. Fleeing hurled explosives, Cap falls into a pit-trap and looks up to see The Swine standing over him. The sadistic dictator prepares to torture the imprisoned Cap with a flame thrower and when Donna Maria attempts to stop his plan, she is hurled into the pit to share Cap’s fate. As the villain prepares to wreak his sinister will, the Man-Fish rises from the river and attacks him and his men…. When Cap and Maria escape from the pit, they find Santiago and his men gruesomely slaughtered—and the Man-Fish coming after them. Cap and Maria are unable to defeat it—until a whistle causes the monster to retreat across the river. Looking up they see the creature’s creator: a cyborg with a transmitter for a head and an enormous face on a viewscreen in the chest—Arnim Zola!