Holmes calls on Watson late one evening to tell him about a case that he has been working on, and also to invite him to be a witness to the final stage of the investigation. He wants Watson to accompany him to Aldershot which is about 50 kilometres south of London.

A synopsis of the case? Colonel James Barclay, of The Royal Mallows based at Aldershot Camp, is dead by violence, and his wife Nancy is the prime suspect.