A man in England, Miller, has stolen some famous and expensive diamonds. You just can't fence this stuff anywhere you like. Miller enjoys showing off to his partner in crime, Dodge, as to his perfect crime in how he plans to fence the diamonds without being detected by anyone. Waite, who now knows how the perfect crime is to be executed, shoots Miller so he won't have to share, but there is still the little matter of the valet who seems quite stoic and practical about the crisscross. While packing to go to the boat, a woman appears and tells the valet that she wants to see Miller. She obviously has some kind of grudge against him, but she she says she will catch up with him later.
At sea, Waite is posing as Miller, and he plans to carry out Miller's plan for fencing the jewels. But the woman who was going to shoot Miller is on board too. The valet Dodge sees her.
Cut to Inspector Carr (John Hamliton) and his friend, Dr, Crabtree (Donald Meeks). They are called to the ship where a body has been found. They quickly figure out that the murdered man in the cabin is NOT Waite, but neither is he Miller. The man who was murdered in the cabin was shot by a woman's gun execution style, in the back of the head. But the woman who has been following Miller/Waite said she was planning to kill her husband and this dead man is not him.
So what happened here? Watch and find out.
This was the last of twelve murder mystery short films shot between 1930 and 1932 in which the team of Inspector Carr and criminologist Dr. Crabtree solve a case with a dearth of clues. It's a well done little mystery done in just twenty minutes.