In a storm off Cape Cod, the Challengers chase a science buoy. They find a Nazi sub drifting on the bottom of the ocean with a crew in suspended animation. The Nazis awaken, capture the Challengers, and plant a super-bomb onshore. The Challengers fight back and reach shore. Prof, who speaks German, heard they were on a secret mission to blow up the Eastern seaboard after the war. With captured weapons, the Challengers shoot back while Prof tries to disarm the bomb. Rocky is captured and steals the PT boat to ram the sub. The bomb is disarmed, ending the last battle of World War II.; The Challengers meet Multi-Woman! She can mechanically morph into a fish, grow wings and fly, and flame on and hurl fireballs. The Challengers dodge her as they finally splash Multi-Man with antidote. He shrinks to his usual form. Multi-Woman is disgusted at this "small and ugly" wretch. When she tries to kill Multi-Man, the villain appeals to the Challengers for help! Returning from the city, Ace drops a giant diamond necklace. What woman can resist diamonds? But when Multi-Woman wears it, Prof throws a switch. Ultrasonic vibrations rattle Multi-Woman to fragments. And Multi-Man got away!; Multi-Man has broken jail, and the Challengers worry where he'll turn up. Soon they learn. Multi-Man launched a rocket with a death ray into space. He threatens to destroy property unless he gets his demands: his own recognized country where crime can run rampant! Meanwhile, the would-be tyrant is lonely. He builds a "queen", a giant female robot, then drinks Liquid Light to become a giant himself. When the Challengers finally track him down, Prof tries to dash the Liquid-Light antidote in his face, but is slapped down.