Plot: This is the story of the biggest spy swap between Russia and the United States since the Cold War involving Sergei Skripal, the victim of the infamous 2018 Salisbury Novichok attack. From the United States ten Russian ‘illegals’, who have, for a decade or more in some cases, masqueraded as Americans and had operated undetected by their neighbours, but not by the FBI, who have had them under surveillance for years