Mio is a girl in high school who slacks off. She and her childhood friend Arata and best friend Madoka spend their after-school days in Ikebukuro hanging out. One day, Madoka tells Mio that she loves Arata, and Mio realizes that she loves Arata, too. But she’s scared of their relationship falling apart and lies, saying she’ll help them. Mio deliberately acts coldly to Arata, and they get into a fight. She decides to work things out with Arata, but gets into a car accident on her way to meet him. She wakes up in a mysterious world. It's the Ikebukuro she knows, but something’s different...
Six months after the events of Magical Girl Lyrical Nanoha: The Movie 1st, Fate has returned to Uminari City with Lindy as her legal guardian and is living the life of a normal elementary schoolgirl along with Nanoha and her friends. The reunion between the two new-found friends is cut short, however, when they are assaulted by four ancient magic users who identify themselves as the Wolkenritter. As the motives behind the actions of the Wolkenritter become clear, Nanoha and Fate find themselves in a race against time to stop the reactivation of a highly dangerous artifact known as the Book of Darkness.
Takamachi Nanoha is a normal third-grader who feels a little useless and out-of-place with no purpose. Then one day, she saves a ferret, who turns out to be a mage from another planet who came to this planet to search for the jewel seeds. Nanoha agrees to help, but this task gets complicated when another girl arrives to steal them.
