This isn't your average sleepover party! The ground is very hard in Nick Tuffle's backyard, and Marvin can't sleep. He's eaten too much cake and drunk too much punch. Suddenly the earth starts to shake. He hears a humming noise, and something zooms across the sky in a bright flash. It's green, like the frosting on Nick's birthday cake. Are candles making it glow? Is it really a flying birthday cake — or something else? And, soon after, there is a new boy in Marvin's third-grade class. He is Joe Normal and hs's turning out to be the least normal person in the universe. He wears the same clothes every day, kisses flagpoles, and has a thing for Jell-O. What in the world is going on?