A US submarine and its crew are captured by the Japanese on the eve of a major WWII battle.

Jim Hardie helps Wells Fargo agents battle the bad guys.

A group of scientists travel to a remote island to study the effects of nuclear weapons tests, only to get stranded when their airplane mysteriously explodes. The team soon discovers that the tests have given rise to crabs mutated into intelligent, impervious, telepathic giants intent on increasing their numbers by breeding, then travelling to populated areas to feed, and which do not intend to be stopped by their discoverers.