The Seal of Dorian

A theft occurs at the British Museum, specifically the seal of Darius, which has been taken without force, indicating insider knowledge of the museum's routine. Sir Henry Bower, an archaeologist in charge of an exhibition, seeks help from a private investigator, Mason, instead of notifying the police. Bower believes he knows where the seal is and suggests that Mason should help recover it discreetly. Mason discovers the connection between the theft and a Greek runner, Popylopedus, participating in an upcoming marathon, theorizing that the location of the seal ties to the race. During the marathon, the Greek runner mysteriously disappears, leading Mason and Bower to a boarding house where they find Popylopedus dead with the seal branded on his throat. They deduce that the theft is tied to a spy ring, with Bower as a mastermind who also attempted to eliminate Mason. Ultimately, Bower is apprehended by police, who find evidence linking him to espionage activities.