Gilligan discovers a steam vent on the island coming up through the ground. Everyone gets exciting, believing they will now have a steady supply of hot water. Later, the castaways learn the steam is due to the presence of an active volcano on the island.

Gilligan accidentally drinks a liquid he thinks is the nitro-glycerin the Professor has been preparing to use to counter the energy coming from the volcano side of the island. Everyone tiptoes around Gilligan, believing any sudden movements will ‘detonate’ him. Later, they discover the liquid Gilligan drank was merely water.

The Professor ends up saving the day by building a bomb device, which when it is activated, somehow stabilizes the volcano.