Nine-year-old Jimbo gets into his fair share of scrapes, but nothing can prepare him for the adventure he and his mate Charlie get into when they plant a walkie-talkie in the staff room and overhear two of their teachers speaking gobbledegook - or is it some secret language? The two boys decide to investigate and become caught up in dangerous events that are, quite literally, out of this world. Mark Haddon's previous books include "Titch Johnson, Almost Champion of the World", "Gilbert's Gobstopper" and "A Narrow Escape for Princess Sharon"