Private investigator Mike Hammer, by assisting a prostitute being assaulted, cannot help noticing a unique ring on her finger. Later, when she is found murdered that ring is nowhere to be found. From here the story moves to a cache of jewelry stolen by the Nazis during World War II and smuggled out of France after the war by an American army colonel, who, together with Mike Hammer, tries to find the ring and recover all the other jewels. However, many parties are on the lookout and the private eye runs into big trouble.