John Sweeney investigates a real-life spy thriller that would baffle James Bond, when ex-KGB spy and Russian dissident Alexander Litvinenko was poisoned and killed by radioactive Polonium 210 in November 2006. The film reveals exclusive unseen footage of Litvinenko in fear for his life, interviews family and friends, former Russian spies, and the Italian businessman Mario Scaramella, while Sweeney investigates the polonium trail, from a piano bar in Mayfair to the walls of the Kremlin itself.