New hire Sayu misses the last train after a company drinking party and invites herself to a coworker's home, knowing his wife has gone to stay with her parents after an argument. Sayu falls asleep as soon as they arrive, and he starts touching her. When she shows no sign of waking, he loses control and penetrates her. Days later, she suddenly returns and blackmails him over that night, turning the tables and toying with him as she pleases.