Boom! Is a roller-coaster read with spaceships, spies and mortal danger! Jim and his best friend Charlie werent looking for adventure, when they decided to bug the staffroom . . . But then they overhear their teachers speaking in a secret language and its too late to turn back. And now they have to explain to the police, the headmistress and their parents where theyve been for a whole week – without mentioning the aliens.