The reader goes back home from school and she finds her parents dead. There's no clues to who might have did it, so they're the prime suspect. They run away from the police and can't go back to their home. They find Deku in an alleyway and he convinces them to join the League of Villains. And they go live with Deku cuz they can't go back home. And that's pretty much it. Oh yeah spoilers Deku is the killer.