Ritsuka Aoyagi is alone in the world--never fitting in at school and alienated from his own past by a fragmented memory. When his beloved older brother is brutally murdered, Ritsuka is heartbroken but determined to find answers. His only lead is Soubi, a mysterious, handsome college student who offers him an intimate link to his brother's other life: a dark and vibrant world of spell battles and secret names.

When Seimei refuses to fight alongside Nisei against an enraged Moonless, it cuts the final tie in the web of manipulation that binds the dirtiest Fighter to his heartless Sacrifice. Meanwhile, while looking at his brother's photo album, Ritsuka discovers new information about his old self that doesn't match up.