In search of a better life, a German girl named Willi joins an American carnival passing through Munich. While traveling from town to town, she is torn between two suitors: cruel carnival barker Joe and kindhearted high-dive artist Frank. Frank gets the upper hand when he asks Willi to join his act. The partners soon become the most popular attraction at the carnival. But tragedy is only a slip away.
Ro-Man, an alien robot who greatly resembles a gorilla in a diving helmet, is sent to earth to destroy all human life. Ro-Man falls in love with one of the last six remaining humans, and struggles to understand how his programming can instruct him to kill her while his heart demands that he can't.