Magical Girl Lyrical NANOHA ..Season 1

Thirty years ago, aliens attacked Earth and nearly brought humanity to extinction. Since then, mankind has clawed for survival, fighting the invaders for land, and the UN established EXCEEDS, an agency to stave off alien threats. On a remote island in a world of chaos, young hunter Shiina yearns for a quiet life with her sister, Setsuna, but a single incident draws her into the larger battle.