Forced to land on a remote island somewhere off the Florida coast, a group of pleasure boaters are attacked by a division of amphibious Nazi zombies. Originally developed by the Third Reich as the ultimate fighting machines, these insatiable undead killers were thought lost at sea when their ship went down in 1945. But in fact, under the command of a demented SS scientist (Peter Cushing), they have been lying low, waiting for the right moment to resume their plans of world domination. Can the pleasure boaters stop this dreadful fascist threat or will they be crushed in the iron grip of these undead übermensch?