Mahou Shoujo Lyrical Nanoha is a magical-girl anime, which started as a spinoff of the visual novel "Triangle Heart 3". Under pressure of circumstances, 9 year old Takamachi Nanoha became a magic girl in order to retrieve Jewel Seeds, dangerous artifacts which were accidentally spread around the world. It has a number of anime and manga sequels.
Mahou Shoujo Lyrical Nanoha is a magical-girl anime series which began as a spinoff of the visual novel Triangle Heart 3. It follows Takamachi Nanoha, a 9-year-old (at the start of the series) who is forced to become a mage to try to retrieve Jewel Seeds, dangerous artifacts which were accidentally spread around the world. Later series introduce a number of new characters and plot lines.
The series has 3 anime seasons, namely Mahou Shoujo Lyrical Nanoha, Mahou Shoujo Lyrical Nanoha A's, and Mahou Shoujo Lyrical Nanoha StrikerS, as well as movies Mahou Shoujo Lyrical Nanoha: The Movie 1st and Mahou Shoujo Lyrical Nanoha: The Movie 2nd A's. There are manga adaptations of all of these, as well as several more manga series in the franchise such as ViVid which has seen an anime adaption and Magical Record Lyrical Nanoha Force.
A New series titled Magical Girl Lyrical Nanoha INNOCENT set is an alternate continuity focuses on a motion based simulation card game. the players of this game are the original series characters like Nanoha and Fate but also characters from the PSP games like the Florian Family and the Material Girls. INNOCENT includes a number of separate Manga series and a web based card game