December 1921: Being single and a new Chief, Inspector Rutledge of Scotland Yard gets the short straw at Christmastime and is called upon by Chief Superintendent Markum to go to the Kentish home of a lord recovering from an attempt on his life. In bed with a concussion, the man is convinced someone is trying to kill him after he claims he was struck by the hoof of a running horse whose rider never stopped to check on him.

Struggling with his own demons from the war and misgivings about helping a man who, as a colonel, oversaw the suffering of those on the frontlines from afar, Rutledge undertakes an uneasy investigation. And as the winter holiday approaches, he becomes increasingly convinced that nothing is as it seems…