The famed surgeon Douglas Stone flaunts his notorious affair with Lady Sannox, although his professional reputation begins to suffer. One night a mysterious Turk asks him to attend his wife, who has cut her lip on a poisoned dagger. The Turk insists that amputation offers the only hope of recovery. Anxious to pocket the proffered gold, and impatient to get to his mistress, Stone dismisses his professional misgivings. He excises the lower lip of the veiled, drugged woman--only to find that he was tricked into disfiguring Lady Sannox herself. Lord Sannox (disguised as the "Turk") thus gains his revenge, with his wife morally chastised (and forever after in seclusion), and Stone's "great brain [thenceforth] about as valuable as a cap full of porridge."