When Alex Rider (Otto Farrant) learns that his Uncle Ian (Andrew Buchan) was killed in the line of duty as a British spy -- and not a car accident like he's been told -- everything changes for this otherwise normal teen. Alex is soon approached by Alan Blunt (Stephen Dillane), head of a top-secret offshoot of MI6 known as The Department, who reveals that he's been unknowingly trained since childhood for the dangerous world of espionage.

Pressured to leave his old life behind, Alex goes undercover to investigate the connection between the deaths of two billionaires and a remote boarding school called Point Blanc. Upon arrival, he discovers that the students are subjects in the megalomaniacal school director's plan led to gain control of their families' business empires. Aided by his classmate Kyra (Marli Siu), best friend Tom (Brenock O'Connor), and his au pair Jack (Ronke Adekoluejo), Alex exposes the plot’s global network and begins his career as MI6's youngest covert asset.