Tony and Doug arrive on the island of Krakatoa the day of its eruption in August 1883 just in time to stop the sacrifice of a young Indonesian by his companions, who are there to serve as guides to Dr. Holland and his daughter. Dr. Holland is conducting a scientific investigation of the island following the loud volcanic explosion a few months before. Karnutu, the chief guide, believes Doug and Tony are devils, who are causing the eruption, and he tries to sacrifice them to the fires to stop the eruption. Doug and Tony find that they have only a few hours to convince the scientists to leave the island before it is blown up with the biggest explosion in history.