Tommy and Tuppence Beresford are approached to take over the International Detective Agency, suspected by the British Secret Service of being a Bolshevik spy information drop. As an amateur private detective, Tommy amuses himself by impersonating great detectives from crime fiction, from Sherlock Holmes to the incomparable Hercule Poirot.
While keeping an eye out for spies, the Beresfords breeze their way through 15 other cases, solving murder mysteries and a jewel robbery, and rounding up gangs of smugglers and counterfeiters.
