Die Schlüssel (1965)

The London fashion photographer Eric Martin expects his brother Philip Martin to return from Germany after a longer period of military service. When he arrives, Philip Martin reports an accident in Hamburg. He should bring items from the victim's wife to Dublin. However, Philip Martin behaves strangely, so that Eric Martin doubts the story. In fact, his brother travels to the Royal Falkon Hotel in Maidenhead and rents a room there.