Alex Rider (Alex Pettyfer) is a normal teenager living with his uncle Ian, a nondescript bank manager... or so it seems, until Uncle Ian (Ewan McGregor) dies in mysterious circumstances. Alex discovers his uncle was in fact a spy and has been murdered by Yassen Gregorovich (Damian Lewis). Uncle Ian had actually prepared Alex for a career in espionage by encouraging his hobbies, and with Alex's skills in languages, scuba diving, mountaineering and martial arts, he has all the attributes of a perfect spy. Recruited by Mr Blunt (Bill Nighy) and Mrs Jones (Sophie Okonedo),and armed with special gadgets, he embarks on his first mission. Billionaire Darrius Sayle (Mickey Rourke) is donating a free Stormbreaker mega-computer to every school in Britain. But is there more to his generosity than meets the eye? Going undercover, he infiltrates Sayle's compound. He meets the tycoon's sinister sidekicks, vixen publicist Nadia Vole (Missi Pyle) and the disfigured mute Mr. Grin(Andy Serkis), and tests out the impressive and secretive Stormbreaker computer. While exploring a restricted area, Alex begins to figure out the mysterious Stormbreakers--he knows he's onto something big. Suddenly, Sayle and his evil henchmen capture Alex. Using his cunning and his MI6 gadgets, Alex manages to escape. He hitches a ride to London to stop Sayle from activating the Stormbreakers and releasing their secret weapon throughout Britain. But time is running out. With the help of his housekeeper Jack Starbright (Alicia Silverstone) and his friend Sabina Pleasure (Sarah Bolger), Alex takes Sayle head-on in a dangerous race against time to stop the evil plan. Wihtin days he's gone from schoolboy to super spy, but will Alex's first assignment be his last?