An extra body is found buried in a grave in a small village where, twenty years ago, an expensive emerald necklace was stolen. Lord Peter must find the killer - and the jewels.

After a car accident in the snow, Wimsey and Bunter are put up by the local country vicar on New Year's Eve, Wimsey stands in for an ailing bell ringer.

Wimsey discovers that the mysterious murdered man spent time in France and travels there to speak to his wife, and with the Vicar's help later later cracks a cipher.

Wimsey hears the confessions of several individuals involving the killing of Deacon and ultimately deduces how the thief met his death.