In the heart of San Francisco, a man was caught trying to break into his own jewelry store at night. During questioning by the FBI, it's revealed that the man's wife is being held hostage at their home by a ruthless extortionist who demands the store's diamonds for her life. In a standoff at the jeweler's home, the extortionist shoots the family's maid and demands to take the jeweler's wife to the docks. FBI agent Warren Stantin tails them, but his attempt to apprehend the extortionist leads to the jeweler's wife being shot in the left eye and killed, while the extortionist has rigged a boat as a decoy and manages to escape.