Yukari Kawahara works at a drink manufacturer. She works hard and achieves recognition for her work. Yukari Kawahara is dating research doctor Kippei Koide. They have lived together for 5 years. One day, Kippei Koide collapses from a brain hemorrhage. Yukari Kawahara soon learns that everything she knew about her boyfriend was a lie. She hires private detective Takumi Kaibara to investigate Kippei Koide.
