Charles Lenox's holiday preparations are interrupted when an officer vanishes at Charing Cross Station. Lieutenant Austen, by all accounts an upstanding member of the elite Grenadier Guards, disappears, and his friends, searching the cloakroom of the station where they had been waiting for their trains together, find only a spray of blood on the wall above a scattering of his personal items—his train ticket among them. Scotland Yard is baffled. Has the Lieutenant, who had a hand in intelligence, been kidnapped by French operatives? Or is there some more personal grudge at work? The situation grows graver by the hour, and Lenox knows that he will have to work quickly and brilliantly to have any chance of discovering the missing soldier—and getting home in time for his own Christmas dinner.