Dr. Thorndyke is asked by a former student to help on his first murder case. A prostitute is murdered and it seemed to be a woman has killed the lady. Dr. Thorndyke helps find the actual murderer with the evidence available.
A quiet, middle-aged couple living in Chelsea start to receive threatening letters through the post - and then things take a sinister turn as their beloved poodle, Tina, is kidnapped. Should they comply and pay up the ransom?
Bill Kirby, an insurance salesman travels back from France by Ferry, where he's pursued by two armed agents. He befriends the innocent Laura, who helps him evade them. A series of murders follow, as Bill tries to unmask who's behind them.