Lucy thinks her little sister, Mia, is a monster. She follows Lucy everywhere, wreaks havoc in her room, and steals her spotlight. When at last Lucy has had enough, she yells, "You little monster, GO AWAY!" But Lucy never imagines that Mia might disappear into a land of REAL monsters! What's a big sister to do? This riotous, honest, and affectionate story will strike a wildly familiar chord with siblings of all ages!