"Seimei refuses to fight alongside Nisei against an enraged Moonless, further straining the manipulative ties that bind the dirtiest Fighter to his heartless Sacrifice. Meanwhile, while looking at his brother's photo album, Ritsuka discovers new information that doesn't match up with what he's been told about his old self"--Back cover.
When the unit named Moonless reveals sordid details of Seimei's past, Ritsuka begins to lose faith in his brother and he is still reeling from this information when Seimei returns to reclaim Soubi.
Soubi, Ritsuka, and Kio set out to find Septimal Moon, and in the course of their journey, Ritsuka must confront his past in the hopes of protecting his future. Nisei and Soubi engage in battle as Soubi's past with Ritsu sensei is revealed.
As Ritsu-sensei, Nagisa-sensei, Soubi, and the Zero Boys observe, Ritsuka talks to Seven through Wisdom Resurrection and finds out a secret about his brother, Seimei.