In this adult role-play, grown middle son Kenji is left living alone with his mother Miyabi after his older brother starts work, his younger brother enters boarding school, and his father moves away for business. The once-lively home suddenly feels empty, leaving Miyabi lost and lonely. Resenting how she always worries about his brothers, Kenji tries to claim all of his mother’s love for himself, pushing their new life across a forbidden boundary.