Sherlock Holmes and Dr. Watson find themselves in a university town when a tutor and lecturer of St Luke's College, Mr. Hilton Soames, brings him an interesting problem. Soames had been reviewing the galley proofs of an exam he was going to give when he left his office for an hour. When he returned, he found that his servant, Bannister, had entered the room but accidentally left his key in the lock when he left, and someone had disturbed the exam papers on his desk and left traces that show it had been partially copied. Bannister is devastated and collapses on a chair, but swears that he did not touch the papers. Soames found other clues in his office: pencil shavings, a broken pencil lead, a fresh cut in his desk surface, and a small blob of black clay speckled with sawdust.
Soames wants to uncover the cheater and prevent him from taking the exam, since it is for a sizeable scholarship. Three students who will take the exam live above him in the same building. The first, Gilchrist, is athletic, being a hurdler and a long-jumper, and industrious (in contrast to his father who squandered his fortune in horse racing); the second, Daulat Ras, is described as quiet and methodical; the third is Miles McLaren, a gifted man but thoroughly dissolute and given to gambling.
Holmes examines the office. The cheater obviously took the papers over to the window one by one while he copied them so that he could see Soames returning, but as it happens, Soames did not come back the usual way. A nearby door leads to Soames's bedroom. Upon examining that, Holmes finds another, similar, sawdust-speckled blob of clay. He stuns Soames by telling him that the cheater, upon hearing his approach, hid in Soames's bedroom. He was there, hiding behind a curtain, all the time that Soames was questioning Bannister.
