Yoshimori's absentee mother, Sumiko, makes an unexpected appearance at Karasumori--but not for a tearful family reunion. Sumiko leads Yoshimori and Tokine through a labyrinth to find and remove the mystical site's mysterious guardian...What does Sumiko know of the circumstances surrounding Tokine's father's death? Can she be trusted? Can Karasumori's guardian be trusted...? And what fate awaits Karasumori if its guardian leaves?!