Captain Brannigan (John Bromfield) and Swede (Lon Chaney Jr.) come across a skeleton at the bottom of the sea. In its hand is a bottle with half a map. They set sail in search of the other half. Complications arise when Brannigan discovers that he needs "The Professor" (Victor Jory) to decipher the map. Loosely based on both The Gold Bug and The Tell-Tale Heart by Edgar Allan Poe.
