After returning home from university, a young man is reunited with his sister, Aki, who has grown into a beautiful woman. When Aki reveals she is being harassed by a man close to their mother, she turns to her brother for comfort and protection. Driven by mutual attraction and a desperate need for safety, the siblings cross a forbidden boundary, beginning a secret and passionate relationship.
This episode follows two separate stories of deception and taboo relationships. Kasumi is blackmailed into a sexual encounter by Kouji, who cruelly mocks her brother Seiichi's obliviousness during a phone call. Meanwhile, a university student returns home and enters into a secret, intense relationship with his sister, Aki, as they both navigate the lies and mysteries surrounding their mother's personal life.