A story to accompany publication of The Medical Casebook Of Sherlock Holmes And Dr John Watson. Dr Watson attends a hansom cab accident on Kensington High Street, in which a fellow general practitioner is seriously injured. Acting as a locum for his colleague, Watson is called to a mysterious death. Sherlock Holmes is asked for help, and discovers another similar death. Unravelling the mystery makes full use of Watson's medical knowledge, but can our heroes prevent further deaths?