Dr. Emil Hartmann, an anthropologist, is studying the Po Ho Indians when they capture him. His wife Dreena calls Dr. Quest for help. The Quest team arrives at the Hartmann's home, determined to recover the doctor. When Dr. Quest examines the spot where Dr. Hartmann disappeared, he, too, is taken! Now Race and the boys must find both men. But why were they taken? The answer is a sinister one -- the men are to be sacrified to the Po Ho fire god in a gruesome ceremony that involves the victims, a pit, and a whole lot of hot coals. Race makes a few engineering changes to the canoes, then dyes himself purple and pretends to be the water god -- if he can distract the Indians long enough, he can free the two scientists. But it doesn't work -- the Indians aren't scared enough of their water god to risk angering their fire god. So Race sneaks back at night, and manages to free Emil Hartmann. But as he's freeing Dr. Quest, a sentry wakes up, and the entire tribe is quickly roused. A chase