In a New York City of the future, almost everyone can fly except for leadfoots like 12-year-old Gurl, an orphan at the Hope House for the Homeless and Hopeless. When she sneaks out one night to rummage for food, she discovers that she can make herself invisible. When Mrs. Terwiliger, the matron who runs the institution, finds out about Gurls ability, she blackmails her into stealing clothing and perfumes and into fixing a $20,000 plastic surgeon bill by hacking into his computer. Bug, a new boy determined to fly, befriends Gurl and the mysterious cat she has found. They run away, only to be caught by notorious gangster Sweetcheeks Grabowski, who realizes that Gurl is a Wall, a person born every 100 years or so who can become invisible. He, too, has designs on her and will do anything to hang on to her. This poor little rich girl story is packed with wildly eccentric characters, such as the Professor, who relies on his Answer Hand, which he bought on eBay, for information. There are also rat men with red eyes and filed teeth, a zipper-faced monster, a cat that showers and blow dries her fur, and mechanical monkeys that absorb the secrets and memories of the orphans.