Stalker: Persona

Mi Jeong, Ji Hye and Ji Hye's boyfriend, Geon Soo, live in the same house. They enjoy having sex without being disturbed by each other. While Ji Hye and Geon Soo are out, Mi Jeong finds Geon Soo's camera and finds out that he is the one who has been stalking her. Mi Jeong wants to ask him about it, but she's already fallen for him. In the end, they turn into a secret relationship. One day, Mi Jeong suggests they stalk Ji Hye.
(Source: HanCinema)