Narrated by Graham Scott

Overworked locum Dr. Jervis is called to the bedside of a gentleman who refuses to see a doctor except on the condition that the doctor must be told neither his name nor his address. After a strange ride in a closed carriage, Jervis finds his patient apparently suffering the effects of morphine poisoning, and departs with a sense of uneasiness. Anxious to trace the man again, Jervis consults his old friend and colleague, the eminent scientific investigator Dr. John Thorndyke - who is himself embroiled in the seemingly hopeless task of disproving the curiously self-defeating second will of the late John Blackmore....