The Disappearance of Mr Davenheim

S2 E6: Wealthy banker Matthew Davenheim leaves his country mansion to walk to the post office after tea and is never seen again. He was expected to meet his colleague Lowen from the 4.45 train but Lowen sees no one on his walk from the station to Davenheim's house. Inspector Japp wagers that Poirot will not be able to solve the mystery without leaving his apartment which, much to the Belgian detective's disgust, he is currently sharing with a parrot.