Dr. John Beck, recently married, decides to take his wife, Cathy, spelunking in Carlsbad Cavern. While there, Dr. Beck, who specializes in bats, is bitten by a fruit bat. He is then, inexplicably, transformed into a vampire bat. While he escapes and seeks help from another doctor, it is clear the treatments are not working. In fact, they are aggravating his condition. Dr. Beck unwittingly goes on a killing spree, catching the attention of Sergeant Ward.

With his assistant, Laura Hutchinson, Dr. David Conway develops a device to advance the fledgling science of earthquake prediction. After forecasting a large trembleor that will rock California within twenty-four hours, Conway cannot persuade the Governor to act. When the prediction proves true and further tests indicate that there are more quakes to come, Conway and Laura seek to perfect their device. Subsequent tests deep within Carlsbad Caverns discover an unknown element—E-112—that is responsible for the earthquakes and threatens to destroy the globe if it ever reaches the surface. The team determines that with only four weeks until Armageddon, the race is on to neutralize the killer element before it takes a devastating toll.