Shinnojo Mimura is a samurai sharing a hand-to-mouth existence with his beautiful wife, Kayo. Frustrated by his lowly status within the castle ranks, Shinnojo dreams of better days instructing children in the way of the sword. But destiny, it would seem, has other plans... A freak accident takes the warrior's sight, leaving Shinnojo cursed. Losing his status and pride, his hopes and dreams, and even himself to this life of eternal darkness, only one path lies open for Shinnojo: that of the true and noble samurai.

After defending the Jewel Seeds and converting her rival into an ally, Nanoha now faces an even stronger foe. The mysterious Book of Darkness threatens to consume its host and engulf the universe if Nanoha can’t overcome its defenses!