"Seven years ago, I killed a man."

Kazuma Waku murdered the man who drove his little sister Yuri to suicide. For that crime, he spent seven years in prison. No matter how much time passes, he can't forget the face of that man dying. However, nothing lingers moreso than the image of that man's daughter, who witnessed her father's murder. Tormented by guilt, Kazuma resolves to make amends by dying.

On the day his mother picked him up from prison, Kazuma went to visit his sister's grave. There, he saw a familiar girl's face.

This is the story of a murderer and the daughter of his victim, a tale rife with drama and suspense.