Four crooked characters will stop at nothing, including double-crossing each other, as they madly search for sunken treasure.

Caine, an American, arrives in a small town in the Sudan after fleeing from Sudanese soldiers who almost caught him with a truckload of illegal arms. Caine meets Doc, an American alcoholic, who informs him that he is being closely watched by police chief Barok and that his only means of escape is by boat. Anna and Dr. Mallare, owners of a boat, enlist Caine's help in what is purported to be an expedition to collect fish specimens. When Caine learns of their interest in a sunken merchant ship which holds $2 million worth of gold bullion, he forcefully informs Mallare that they are now partners. The next day Caine and Mallare cut through the ship's hull. While transferring the bullion to the boat, Anna baits the sharks with bloody pieces of fish. Mallare is killed, but Caine escapes and knocks Anna unconscious. Police chief Barok arrives and attempts to steal the gold from Caine, but Caine hurls him into the shark-infested waters. Anna revives, orders Caine onto the police launch, and takes off in her boat without knowing that the ballast valves are open and the ship will sink.