Science magic (a big hero 6 fanfic)

Luna, an young genius moves away from her town to get over her dark past and to start a new life. Gave up the idea of superheroes when she lost her only side kick and best friend. But circumstances changes when the one supposed to be dead comes back and attacks the city of San Fransokyo. Luna is in a dilemma whether to fight back or to remain silent and move on with her life. Can't afford lose another friend, can she?. Also, there is suspicious appearance of creatures unknown to the world of humans and its language understood by none but her.