Originally Aired: July 2, 1957

In A Case For Doctor Morelle #11, "The Gambler," the famous detective and his secretary Miss Frayle are drawn into a puzzling case when they stumble upon a ringing telephone box during an evening walk. Answering the call, they hear the frantic voice of Mrs. Ludlow summoning a doctor to her Chelsea home, convinced something terrible has happened to her husband Alex. The distressed woman explains she returned early from a party, gripped by a premonition of disaster, but was too frightened to enter her husband's study herself. When Dr. Morelle and Miss Frayle investigate, they find the room empty, despite Mrs. Ludlow's certainty that her husband was inside.

As the episode unfolds, hints emerge about Mrs. Ludlow's dangerous gambling obsession, particularly her reckless behavior at the roulette table where she loses considerable sums. Dr. Morelle observes that she exemplifies the gambler's fallacy, refusing to accept that each spin of the wheel is independent of the last. The case promises to spiral into what Dr. Morelle describes as a vortex of disaster and death, with Mrs. Ludlow's compulsion at its center.