 Six months after the original series, she and Fate encounter the "Wolkenritter", four magic knights who steal others' magical abilities to save Hayate Yagami, a wheelchair-using Japanese girl.Since the Wolkenritter are skilled in Ancient Belkan combat magic far superior to theirs, Nanoha and Fate fail to stop them and the Book of Darkness, an ancient artifact bound to Hayate, is activated.A worldwide catastrophe is only prevented thanks to TSAB and most importantly, Hayate's intervention.