Nanoha Takamachi is a normal 3rd grader until one day she meets an injured magical ferret that communicates with her telepathically, begging her to save it. When she does, the ferret gives her his magical bead, Raising Heart, to transform into a magical girl. It turns out she has a lot of magical power. She takes over the ferret's job collecting dangerous magical relics called "Jewel Seeds", and meets another magical girl and rival, Fate Testarossa, in the process, who Nanoha fights to befriend.
This show is REALLY cool, and has technological magical girls blasting laser beams of friendship. But at the same time it has fanservice...of 9 year olds... ughhh