United States

Charter air pilot Grant Murdock and his passengers, alcoholic film star Laura Winters and her secretary Jan Letterman, are forced down in a storm on an apparently deserted island. Out at sea, wearing frogman's kit, comes a mysterious marine biologist, Peter Bartell, who is studying a new form of marine life - minute silvery creatures that are voracious flesh eaters. A skeleton is washed up and they discover that the sea is literally full of these glowing organisms. Overnight Murdock's plane disappears and the party are stranded. A beatnik named Omar arrives on a raft and, despite shouted warnings from the shore, insists on landing. It transpires that Peter Bartell is conducting secret experiments to control the menacing organisms with a view to using them to further his own mad purposes. Bartell kills Omar and stabs Laura, burying her body in the sand, although, unknown to him, she is still alive. An attempt is made to electrocute THE FLESH EATERS but the efforts only cause the creatures to multiply and join together into a single glutinous carnivorous monster. Laura revives and tries to stab Bartell, but he shoots her. As she dies, blood flows into the nucleus of the monster and destroys it. When a second and even larger monster arises from the ocean, the survivors plan to kill it with an injection of their own blood. A hand to hand struggle ensues between Grant Murdock and Peter Bartell, as a result of which Bartell is thrown into the sea, where he is quickly reduced to a skeleton by the organisms. Murdock succeeds in destroying the huge creature by injecting human blood into its one immense eye.