Li Na‑mi’s lost smartphone ends up in the wrong hands. The perpetrator arranges everything in such a way that the girl comes to pick up the phone at his service center and gives him the unlock code — he installs a spyware program on the device and can now monitor every step of his victim. Meanwhile, the bodies of several girls are found outside the city, and the police detective begins to suspect that his son, who ran away from home several years ago, is connected to these murders.