The dumping of radioactive waste in the ocean disturbs a prehistoric monster than can project electric shocks and radioactive beams. After terrorizing the English coast, it is discovered that if the creature is destroyed with conventional weaponry it would spread a dangerous amount radioactive contamination over the entire country, with this fact preventing the military from attacking the monster as it nears London.—Jeremy Lunt
Marine atomic tests cause changes in the ocean's ecosystem resulting in dangerous blobs of radiation and the resurrection of a dormant dinosaur that threatens London.