Tom and his partner, Marcel, move into their first shared apartment. The twosome could be very happy together, however, every night, Tom hears strange noises and discovers a door to the neighboring apartment that stands wide open. The key is missing, and all attempts to lock the door fail. As Tom grows increasingly afraid of what is lurking there, Marcel worries about their newfound happiness and tries to downplay the situation. Even when they realize that the man living on the other side is Adolf Hitler and has no intention of leaving them in peace. When his trust in Marcel ultimately crumbles, Tom has to confront the door on the right by himself.