A single middle-aged man picks up a cellphone dropped by a female student in an underground passage. Back home, he discovers masturbation videos on the device, which the girl had apparently sent to her lover and boyfriend. The next day, he blackmails the student who is searching for her lost phone, taking her to a nearby mixed-use building where he tortures her with electric vibrators and dildos, filming her lewdness on the cellphone as she writhes and climaxes repeatedly. Later, he takes the girl to his house, forcibly creampieing her and repeatedly assaulting her.