Hot water spurting from beneath the island pleases the castaways as they can now have hot water piped to their huts. However, the hot water also concerns the professor since it means that increased volcanic activity may be imminent. The Professor saves the day by making a bomb from ingredients found on the island (of course!) to spike the volcano.
Elenco: Bob Denver , Alan Hale Jr. , Russell Johnson , Jim Backus , Natalie Schafer , Tina Louise , Dawn Wells .