Collegiate Komugi Yamashita lives with her retired policeman father, having lost her mother early on. But then her father is murdered, leaving only a letter cryptically naming a certain person as innocent should he ever be arrested or prosecuted. Learning the suspect is the son of a criminal executed 22 years ago, Komugi seeks the help of a lawyer Matsukaze named in the letter. But Matsukaze has never had any contact with Komugi's father. So the two go in search of the shocking truth.