As per Nona's request, Decim is sent two new guests; a young man named Shimada and a detective named Tatsumi, one of whom is allegedly a murderer. While searching for a way out, Shimada finds a blood-stained knife among his belongings, unsure of where it came from. As the two guests participate in a game of air hockey, Shimada gradually regains memories of looking after his younger sister while Tatsumi remembers that his wife was murdered. With the two regaining further memories that fuel their motivations to escape, with Shimada remembering his sister was assaulted, Decim changes up the game, in which scored pucks deal pain to the respective player's organs. Meanwhile, the black-haired woman makes a request to see the memories that Decim received and learns that both Shimada and Tatsumi are murderers.