One wretched November night, Inspector Stanley Hopkins visits Holmes at 221B Baker Street to discuss the violent death of Willoughby Smith, secretary to aged invalid Professor Coram. Coram had dismissed his previous two secretaries. The murder happened at Yoxley Old Place near Chatham, Kent, the fatal weapon being a sealing-wax knife belonging to the professor. Hopkins can identify no motive for the killing, with Smith having no enemies or trouble in his past. Smith was found by Coram's maid, who recounts his last words as "The professor; it was she."

The professor's study contained a bureau; nothing seemed to have been stolen. Its drawers were left open, as was normal, and the cupboard in the middle was locked. The professor kept the key. A lone piece of evidence was found in Willoughby Smith's hand: a pair of golden pince-nez spectacles. Holmes examines these and from them alone deduces the following details of the murderer: