Theresa, a British agent, monitors German U-Boats on the southern South African coast. She falls for a Nazi sympathiser whom she accidentally kills. While on the run she discovers treasure from a wrecked galleon hidden by the enemy. In the present day she is murdered and her niece, Penny, a glamorous journalist, becomes a target for a sinister Neo Nazi organisation, headed by an English judge, after the treasure and revenge for their agent's killing. The conflict moves to a climax in the caves of of the southern Cape coast.