Tanya Majors was a bright student in her old highschool, who was sadly always getting the short end of being hassled by bullies. Especially Sasha, a tough, brawny lioness who was constantly terrorizing everyone. So one day, Tanya cobbled together a super-science chemistry lab in the basement, and after multiple experiments, she brewed up the first version of her morph suit, a suit of flexible smart polymer that reacted to different kinds of electrical impulses. After going through a few more versions and designing a wearable control system for it, Tanya finally decided to teach Sasha a lesson.
Confronting her after school with her new suit, Tanya launched herself at Sasha to delivery a savage beating... ...only to discover to her shock (and everyone else's) that Sasha wasn't just strong, but super-strong. The ensuing battle ended with the local STAR (Superhuman Tactics and Response) squad getting called in, and both Sasha and Tanya getting arrested.
Tanya still doesn't know what happened to Sasha, but she was in trouble herself. Beyond the superhuman battle, Tanya had a history of shenanigans in class, especially pranks aimed at her creepy chemistry teacher, and this was basically a "strike three". Tanya was given a psychological examination, and was diagnosed with a mild form of Science-Related Memetic Disorder. AEGIS investigators became involved, and one of them offered Tanya an alternative to Juvie: a transfer to Claremont Academy, a school for superpowered teens, for which someone like her was well suited.