About:
It rises from 2000 miles below the earth to melt everything in it's path! When a fissure explosively opens in an English mud flat during a military exercise there, injuring one soldier and killing another, an American research scientist at a nearby nuclear plant joins with a British investigator to discover why the victims were radioactively burned and why, shortly thereafter, a series of radiation-related incidents are occurring in an ever-growing straight line away from the fissure.