Mahou Shoujo Lyrical Nanoha: The Movie 2nd A's

Months after the Jewel Seed incident, Nanoha Takamachi looks forward to welcoming Fate Testarossa into an ordinary school life. Their reunion is interrupted when four powerful knights attack them, drain their magical energy, and feed it into an ancient grimoire known as the Book of Darkness.

The Wolkenritter are acting for Hayate Yagami, a gentle girl who has no idea how dangerous the book bound to her truly is. They believe completing it can save their beloved master, while Nanoha, Fate, and the Time-Space Administration Bureau know its awakening may cause catastrophe. As both sides fight for someone precious to them, the conflict becomes less about defeating an enemy than finding a way to break a curse without sacrificing Hayate.