Skeleton Key — Anthony Horowitz

DESPERATE!
Working as a secret agent for Britain's most exclusive agency, Alex Rider thinks he's seen it all. He's been shot at by international terrorists, stood face-to-face with pure evil, and saved the world -- twice. All before his fifteenth birthday. But Alex is about to face something more dangerous than he can imagine: a man who's lost everything he cared for -- his country, his son -- a man who has a nuclear weapon, and will stop at nothing to get his world back. Unless Alex can stop him first....