[Machine Translation] Tsunade, a graduate student in the history department, is obsessed with ancient documents and is called a "decipher" by those around him. Tsunade is assigned to return an ancient manuscript found in his laboratory, and visits a small island in the Seto Inland Sea. Tsunade is pushed around by his companion, Soma, a troublemaker, but after completing the return, Tsunade encounters a series of murders... The murders are modeled on the "legend of Haku-Myohime," a girl believed to be the reincarnation of Haku-Myohime, and a mysterious journal with missing contents. Tsunade deciphers old documents and sheds light on the truth hidden in the shadows of history.