Harry and Fergus take on a disturbing case-a serial killer targeting random victims and leaving a coin in their mouths. Meanwhile, Harry B. asks a reluctant Harry to travel the world with him. Fergus plans to attend college with Lola.

Harry and Fergus travel to the convent of a silent order of nuns after an old friend asks Harry to investigate a suspicious suicide, believing foul play is afoot. Elsewhere, a familiar face provides a very welcome surprise.

A fun day at the races for Harry and Fergus ends in tragedy when a racehorse throws its jockey from the saddle. Harry B discovers the horse was sabotaged and insists the owner, his father, Duncan, is responsible for the crime.