Passengers travelling on a delapidated steamer find themselves marooned on a misty sea, surrounded by killer seaweed, murderous crustaceans and Spanish pirates. Fantasy Hammer horror, starring Eric Porter, Hildegarde Knef and Suzanne Leigh.

An eclectic group of characters set sail on Captain Lansen’s leaky cargo ship in an attempt to escape their various troubles. When a violent storm strikes, the ship is swept into the Sargasso Sea and the passengers find themselves trapped on an island populated by man-eating seaweed, giant crabs and Spanish conquistadors who believe it’s still the 16th century.