In a retro-futuristic America, ten-year-old Byron "Boon" Barnett boards a rocket-ship with his family for a move to the Moon. The Barnetts are a contemporary clan: Mr. Barnett is Anglo; Mrs. Barnett (the former Bianca Barcelona) a Latina; Boon's teenage brother, Taji, is adopted from Kenya; and Boon himself is a one-of-a-kind.

Also moving to the Moon is Boon's crabby partner-in-crime: José Ignacio, a seven-foot-tall, old-school robot. In reality, José Ignacio is a twelve-inch toy; but in Boon's fantasy life, the robot is one half of a danger-seeking, dimension-hopping duo.

On the ride up Boon makes a new frenemy in the eccentric Englishman, Lucky von Stroganoff. Meanwhile, girl-crazy Taji falls hard for the Governor of the Moon's fearless daughter, Xing-Xing, a Lunarian of Chinese heritage. And then there's ten-year-old Honeybun, Boon's new classmate from Jaipur, India: the smartest kid in the whole history of the lunar school system.

But danger is looming as a stellar phenomenon wiggles to life in open space and starts bombing the lunar city with chunks of gobbled planets. Colonists pile into the lunar life-raft to escape--except for the Barnetts and their friends, who get left behind.

Boon insists he knows how to save everybody, but here's the problem: people tend not to believe him about stuff. His parents have been lecturing him for a while now on the dividing line between using his imagination for fun and using it as an excuse for bad behavior. Suddenly it's the dividing line between life and death.