The murders start with the body of Robin. He is found with a arrow through the heart, but Vance deduces that the body was placed and not found where he was killed. The note found dealing with the murder was part of a nursery rhyme and signed by 'Bishop'. The only witness may have been Mrs. Drukker and Adolph, but they are not talking. As the murders progress, each one is accompanied by a nursery rhyme. It is up to Philo Vance to unravel the clues and unmask the identity of the murderer 'Bishop'.

Clint Belmet is a bit of a firebrand and is sentenced to at least 30 days in jail, but his partners, Bill Jackson and Jim Bridger talk a sympathetic Frenchwoman named Felice into telling the bumbling, drunken marshal that Clint had married her the previous night. Clint is released so he can accompany Felice on the wagon train heading west to California.