Holmes receives a mysterious telegram from Cyril Overton, the captain of the Cambridge University rugby team. Overton later explains that one of the best players on his team, a young man named Godfrey Staunton, went missing while in London for an important game. Holmes follows a trail of clues back to Cambridge. He suspects Dr. Leslie Armstrong of Cambridge of having something to do with Staunton's disappearance. Dr. Armstrong's refusal to cooperate with Holmes and the lengths which he goes to in order to prevent Holmes from following him seem to bear out this suspicion. With the aid of a dog which has been trained to follow scents, Holmes tracks down Dr. Armstrong and finds out the truth behind the mystery.