This book is about a girl named... well... Gurl. She lives at Hope House for the Helpless and the Hopeless Orphanage. She has no friends, and Digger is constantly picking on her. Everything stays the same, until one night, at the back of Luigi's, a cat decides to choose her as her owner. She has to keep the cat hidden from everyone else at Hope House. Also, everyone there can fly, except Gurl. She can turn invisible, though. A new boy comes to Hope House, named Bug. Together they sneak out from Hope House and the evil matron, Ms. Terwiliger, who makes them steal for her. They find out that they accidentally took one of the matron's monkeys with them when they left. They give it money (don't ask why) and the monkey reveals secret to them that they never imagined. Bug is the son of the most famous gangster ever, Sweetcheeks Grabowski. Sweetcheeks just so happens to be where they were when the monkey screeched the secrets, and takes Bug and Gurl to his lair. They battle Sweetcheeks and his sidekick, Odd John, until Odd John dies, and Sweethcheeks is arrested. Gurl finds out that her parents are actually The Richest Man and The Richest Woman in the Universe, making her The Richest Girl in the Universe. Bug lives with Gurl (her real name turns out to be Georgie) and her parents, since his mom is dead, and his dad is a busted, washed-up gangster.
This book teaches that no matter what, friends stick together. Because, at first, Gurl didn't trust Bug after they found out he was a gangster's son. But then he realized that he is a good person and does not even want to be a gangster.