Magical Girl Lyrical Nanoha A's

After the Jewel Seeds incident is resolved, Nanoha Takamachi slips back into ordinary days—now punctuated by early-morning magic training. She keeps in touch through video messages with Fate Testarossa and the Arthra’s crew, looking forward to the moment they can meet again in person. That calm is shattered when Raising Heart suddenly senses danger and warns Nanoha of an imminent attack.

The assailant is Vita, a self-proclaimed Belka Knight wielding an intelligent device powered by a strange cartridge system, and her overwhelming strength quickly corners Nanoha. The Space-Time Administration Bureau arrives in time to intervene, revealing that Vita is not alone: Shamal, Signum, and Zafila are also targeting mages to siphon their power. Their goal is to complete the Book of Darkness, a Lost Logia—leaving the question of what they intend to do with it hanging ominously over Nanoha’s next battle.