In the story, the brilliant consulting detective Sherlock Holmes is contacted by John Mason, the head trainer at the Shoscombe stables. Mason is alarmed by the strange behavior of his employer, Sir Robert Norberton. Sir Robert is heavily in debt, and he has bet everything he can raise on his horse in the upcoming Derby in the hope of re-establishing himself. The stress has been too much, and Sir Robert has not been himself for the past week. He appears to have quarreled with his ailing sister, Lady Beatrice, upon whom he is financially dependent. He has stopped spending evenings with her, and he has given away her beloved pet spaniel. He has also been seen going into the old church crypt at night with a stranger. Holmes is initially unsure what is to be done about the matter. When Mason pr