Alex Rider (Alex Pettyfar) is a normal teenager who lives with his uncle, a nondescript bank manager... or so it seems, until Uncle Ian Rider (Ewan McGregor) dies in mysterious circumstances. Alex discovers his uncle was in fact a spy and has been murdered by Yassen Gregorovich (Damian Lewis), one of the most dangerous assassins in the world.

Recruited by Mr. Blunt (Bill Nighy) and Mrs. Jones (Sophie Okonedo of the Special Operations Division of MI6, the schoolboy realizes that by encouraging his hobbies his uncle has thoroughly prepared him for a career in espionage.