Seventies and early eighties British children's television programme, animated. Mr Benn is a respectable city worker, looks like a banker, really, who stumbles on a fancy-dress shop and proceeds to try on costumes on a weekly basis. He never hires or buys anything - he just tries them on.
When he is costumed (as a knight, or a jester, or a spacemen etc.) he leaves the dressing room by a different door and finds himself in another world. This world has a problem of some sort that only he, as his new character, can fix. So he, inevitably, does. At the end of the adventure a man, curiously resembling the shopkeeper, materialises ('as if by magic, the shopkeeper appeared') and leads him through a door back to the changing room.
Mr Benn changes back into his pinstriped suit and bowler hat. The shopkeeper does not seem to expect, or require, payment and Mr Benn leaves and returns home. On the way he realises that he has something in his pocket from the other world and he decides to keep it with his growing collection of memorabilia. Inventive, magical and great fun (although Freud would probably have had a field day working out what it all meant).