While on holiday in France, there is a murder at the docks and Colonel March is asked by a friend of the French police to assist. The only clue left behind by the culprit, a sailor's cap - "looking for the head that fits this hat."

Two Mona Lisa paintings appear on the art market | but which one is the second original and which is the copy? Colonel March is determined to reveal the truth.

A 12 year old boy insists his dead father told him to kill his mother's new fiancée. But did the father truly die in an accidental plane crash?

Colonel March hypnotises five people to solve the stabbing murder of Lord Telford, while he himself portrays the murder victim.

Colonel March is called in to investigate a murder in a beauty salon. There are plenty of suspects and it's up to Colonel March to single out the murderer.

A scientist conducting cancer research is convinced that his test monkey was not only stolen but replaced. He is later found dead from gas, and Colonel March must prove if it was suicide or not.

A man demands to be arrested for plotting the perfect murder of his wealthy wife, who is found dead that night of natural causes. A valuable coin collection holds the answers.

A bank robbery takes place and the suspect, never out of sight, is followed to his office, where he locks himself in. But when the police and Colonel March search his office there is no trace of the money!

A skull, known as the Damascus man, is stolen from a museum and Colonel March's life is imperiled trying to solve the case.

A phony spiritualist believes she's truly summoned a real ghost. Colonel March attends her next seance to discover the identity of the spirit's killer - dead or alive.

A woman is found dead, but was it suicide or murder? A French fencing match provides the telling clue and Inspector Goron travels to London to assist Colonel March.

When a wife reports her reclusive mystery writer husband has accidentally fallen from a cliff, suspicion points to her as the killer. Colonel March is called in to investigate at the isolated seaside manor.