Sixth grade has been pretty disaster-free for aspiring astronaut Maple McNutt-which is impressive, given the number of worries and possible catastrophes that run through her head every day. (So far, Earth hasn't been devoured by a black hole and a cockroach hasn't crawled out of her toothpaste mid-squeeze. Phew!) But then her best friend of seven-point-two years, Sunny Gwon, accuses her of being unfun and starts hanging around with a new group of friends.