- Genres: Mystery
- Running Time: 119 min.
- Directed by: Pang Eun-jin
- Starring: Lee Yo-won, Ryoo Seung-bum, Cho Jin-woong
Synopsis: Seok-gu showed a lot of promise as a brilliant mathematician when he was in school, and resolutely focused on his studies rather than on friends throughout his childhood. Now in his 30s he's an ordinary high school math teacher, a far cry from the promising future of his youth. His morning exchanges with Hwa-seon, the shopkeeper he buys lunch from, is the brightest part of his day. During a violent altercation with her ex-husband where he mercilessly beats both her and her niece, Hwa-seon kills him. Seok-gu overhears the fight from his house next door and decides to cover up the killing and protect her from the police. He plans the perfect alibi for her and thanks to his efforts Hwa-seon is never much of a suspect in the case. However, the detective in charge, Min-beom, believes that Hwa-seon is indeed the killer and follows his instincts.