In Taipei's pricey Gongguan district, you rent a 1980s apartment room for an absurd 3,000 NTD/month alongside three mysterious roommates: a gentle medical senior washing bloody coats at midnight, a tattooed Daoist bassist, and a nocturnal paranormal streamer. A yellowed 'House Rules' sheet warns: 'Never open the door to marble sounds after midnight; go downstairs if 5F lights up; whatever knocks after 1 AM isn't human.' Then your crush dies on the 4.5F stairs—and a neighbor's telephoto lens reveals the figure who lured him to 5F was wearing your jacket...