On a rainswept London night, the wealthy unscrupulous Robert Kramer hosts a party in his penthouse just off Trafalgar Square. But something is wrong. The atmosphere is uncomfortable, the guests are on edge. And when Kramer's new young wife goes to check on their baby boy, she finds the nursery door locked from the inside. Breaking in, the Kramers are faced with an open window, an empty cot, and a grotesque antique puppet of Mr Punch lying on the floor. It seems that young Noah Kramer was thrown from the building, but the child was strangled, and the marks of the puppet's hands are clearly on his throat...what's more, there was a witness. It's a perfect case for the Peculiar Crimes Unit. As John May and his team interrogate the guests, Arthur Bryant heads into the secret world of automata and stagecraft, illusions and effects. His suspicions fall on the staff of Kramer's company, who have been employed to stage a gruesome new thriller in the West End. As a second impossible death occurs, the detectives uncover forgotten museums and London eccentrics, and take a trip to a seaside Punch & Judy show. Then Bryant's biographer suddenly dies. Was it a tragic accident, or could the circumstances of her death be related to the case? There's just one hour left to solve the crime, but Bryant has buried himself away with his esoteric books. The stage is set for a race against time with a surprising twist...