Mr. and Mrs. Elder had a break-in and nearly 3,000 £ were stolen together with some petty stuff. The petty stuff is promptly found. It was thrown from a moving car and landed on Dr. Merrick's lawn. Later Dr. Merrick also identifies the car as the one belonging to the Elders. This puts Mr. Elder in the hot seat as the prime suspect, because he does not have an alibi. The solicitor Helen Aves is looking for Winston and Reginald Parker, the relatives of a client. Sergeant Merton assigns the case to Alf Ventress, who is now working as a civilian at the police station, but Oscar Blaketon has already offered his services as a private investigator as well. They join forces and hire David as a driver. But that is just about the only thing the two sleuths agree on.