Sigmund Rosenblum is on a mission in Russia. His train is stopped and he is arrested, but he escapes and travels to London. There, he compromises Margaret Thomas, the young wife of a rich clergyman. Her husband dies, Rosenblum marries her, takes her maiden name (becoming Sidney Reilly) and is posted to the Far East.
Intelligence from Reilly in Port Arthur enables the Japanese Navy to sink the Russian Pacific Squadron. Margaret Reilly has an affair with Greenberg and leaves her husband. Reilly is seized by the Russians.
Reilly is posted to a German munitions factory, with the mission of stealing the designs of a new naval gun.
Reilly is in France, searching for Margaret, his wandering wife, and an Australian oil tycoon, and also competing with the Rothschilds to buy oil concessions in the Middle East. While Reilly is in Paris, he meets his long-lost half-sister, Anna, and we learn more about their beginnings in a prominent family in Odessa. But Anna kills herself, amid strong intimations of incest.
On a mission to St Petersburg, Reilly investigates a deal for German shipyards to rebuild the Russian navy.
Reilly is still in St Petersburg, and his mission there succeeds - he gets hold of the naval contract between the German and Russian Empires. Meanwhile, Reilly has fallen in love with Nadia, the wife of his friend Count Massino, and his lawyer friend Grammaticoff has some advice for him.
Reilly and Grammaticoff arrive in Moscow with a million dollars in cash. Reilly plans to overthrow the Bolsheviks, who are in the process of making peace with Germany, and to replace them with a new Russian government led by him. Once in power, Reilly plans to renew the war against Germany. Meanwhile, the British are planning an invasion of Russia.
Reilly makes careful plans to take control of Moscow, but his coup misfires when Lenin brings forward a meeting of the Congress. Then most of Reilly's friends are arrested by the secret police after an anarchist makes a bungled assassination attempt. Lenin survives being shot, and Reilly flees Moscow.
Reilly is back in London, where he arranges a loan of $250,000,000 for the Bolsheviks. While they are in London, a revolutionary tribunal in Moscow sentences Reilly and Bruce Lockhart to death, in their absence - and Reilly survives an assassination attempt in London.
It's New York, in the year 1924, and Reilly persuades Henry Ford to put up the money for an invasion of Russia. But Reilly is betrayed by Eugenie, his secretary, and kills her. In New York, Reilly finds Nadia Massino - and he makes a hit with Pepita. Meanwhile, the Zinoviev Letter is published in The Times of London (25 October, 1924), a few days before the British general election. It seems to be a letter from Zinoviev, head of the USSR's Comintern, to communists in Britain, and is a huge embarrassment for the British Labour Party. The Conservatives win the election and Anglo-Soviet treaties are abandoned. So is the Zinoviev letter forged or genuine? Reilly is a key player.
Reilly marries Pepita, then he seeks revenge for the death of Savinkov. He arranges for Stalin to arrest him, destroying the Trust backed by the Cheka.
Reilly disappears in Russia again, and this time Pepita goes to look for him. He is in the Loubianka, being tortured. The British prime minister, Stanley Baldwin, considers mounting a rescue attempt, and Stalin gives orders for Reilly to be killed.
History Channel overview of Sidney Reilly followed the last episode of Reilly.
