Alone in Challenger Mountain, June experiments on space spores brought to Earth by a balloon. They explode and she blacks out. The Challs return to find June is giant-sized and hostile, trying to crush them, but she passes out. Another menace is a huge red dragon-beast menacing a local town. June revives, sensible again, and grapples the monster. The beast avoided crossing a stream, so the Challs commandeer a fire truck and hose it. The beast shrinks to nothingness. It was actually a microbe monster!; Multi-Man survives an explosion which gives him super-strength. He escapes prison and meets with Gurk, who wants Multi-Man to help him collect parts of a statue. After Multi-Man steals a part of the statue, the Challs follow him to Central America where Gurk and Multi-Man have gone for the last piece of the statue. The Challs revert Pramble to his normal form, as Gurk uses the statue to unlock a lost tribal treasure. Escaping, Pramble is speared by natives and emerges as a super-genius in a frail body with a giant head. But the natives help capture Gurk and Multi-Man and reclaim the treasure.