Axel, a little boy who never used to want to tidy his room, has now become a neat-freak. He carefully arranges his superheroes by size and color and meticulously refines his models. But then, a little sister comes along–and by "little sister", I mean a dreadful monster who wreaks havoc among Axel’s toys... Living together is going to be tough! Especially since the meglamaniac little sister has a secret weapon: whenever someone tries to stop her, she triggers an ultrasonic alarm, which brings Mum and Dad running! And guess who's the one who gets it in the neck?