Since moving into their new rental apartment in central Tokyo, Eri's married life has taken a drastic turn. Their neighbor, Kanno, appears friendly at first glance, but in reality runs a shady investment business from home. He sets his lewd eyes on Eri and gradually begins closing in on her. Meanwhile, her husband Koji, increasingly busy with his job at headquarters, remains oblivious to his wife's growing sexual dissatisfaction—and completely unaware of the developing relationship between his wife and the neighbor. Amid this tension, Eri is drawn deeper into a dangerous situation.