The episode's plot revolves around the ancient map of 'The Lost Mine'. A chinese man is skilled before he could sell the map to a pretigous English bank and the General Manager asks Poirot to look into the matter. Poirot is a member of the bank and before he knows the Chinese man is missing/dead he is told by his bank that his bank account is overdrawn - this act sends him into an embrassing argument with the teller ( not realising that Ms Lemmon had negelected to bank a cheque from a former client). Whatever the reason his confrontation with the teller is very funny. This episode is one of my favourites and i find Poirot's take on the game on monopoly wonderfully thoughtful.