Elementary school student Nanoha Takamachi meets the mysterious ferret Yuuno who needs her help to seal up powerful Jewel Seeds that accidentally landed on Earth. Given a magical device called Raising Heart she transforms into Magical Girl Lyrical Nanoha and wields a staff to seal the evil within the Seeds, but will soon confront Fate Testarossa, a magical girl from another world, who also wants the dangerous Jewel Seeds. With the appearance of the Time-Space Administrative Bureau, Nanoha, who wants to be friends with Fate, is going to face a long battle.
