The story features an arrogant surgeon, Douglas Stone, who is in love with the married Lady Sannox, one of the most beautiful women in London.
On his way to a rendezvous with her, the surgeon is asked by a Turkish man to operate on the latter's wife, who has cut her lip with a poisoned scimitar.
Because of his desire to meet his lover, his need for money, his professional arrogance, and the opinion of the Turk that any delay would kill his wife, the surgeon goes ahead with the operation on the heavily drugged wife, whose face is obscured by a veil.
After he has performed the operation, Dr. Stone realizes his patient is Lady Sannox, and the Turk her husband, who believes the disfigurement will be morally good for his wife.
[2] In the episode, which is set after the events of the original short story, Holmes investigates the cause of Dr. Stone's mental breakdown.