This is the story of Oleg Gordievsky, one of the West’s most valuable Cold War agents who risked everything to avert a third World War. Appearing to be an ambitious diplomat stationed at the Soviet embassy in Denmark. Gordievsky was actually a Russian spy and a rising star of the KGB. After a few years in Copenhagen, he was recruited by the British and posted to London by the KGB. Whilst in London, President Reagan authorised the largest NATO war game in its history: Able Archer.

This is the story of the biggest surveillance operation in British history, and how British intelligence agencies and their allies thwarted the deadliest terror plot ever devised on home soil. In June 2006, Abdullah Ahmed Ali flew back from Islamabad, Pakistan to return to his east London home. Ali had no idea he was being watched by the British security service, MI5. The airport discovery marked a critical moment, as they found a collection of batteries and a large bag of the soft drink powder.

This is the story of Robert Hanssen - a former FBI agent who systematically dismantled the United States’ network of undercover Soviet agents, from the inside out. His espionage was described by the Department of Justice as "possibly the worst intelligence disaster in U.S. history”. Hanssen spied for Soviet and Russian intelligence services against the United States from 1979 to 2001 and his actions pitted CIA against FBI and triggered a mole hunt that brought the American intelligence services to their knees.

This is the story of eight filmmakers sent to Tehran to scout locations for a big budget, Hollywood-produced sci-fi fantasy film as depicted in the award-winning film Argo. In January 1980, two CIA agents and six employees of the US embassy in Iran arrived at Mehrabad Airport, Tehran with fake passports, papers and scripts. This is the remarkable story of how one man used inspiration from Hollywood to school six frightened diplomats in the art of ‘being someone else’, and score a victory for the CIA, in one of the darkest moments for American foreign policy.

This episode tells the amazing story of Vladimir Vetrov, a high-ranking KGB officer and secret operative for the French Intelligence Service, during the Cold War. In December 1980, he made the decision to spy for the French Intelligence Service after spending a number of years in Paris. As a secret agent Vetrov passed more than 4,000 documents to his handlers revealing the extraordinary depth of the Soviet industrial espionage mission against the West. President Ronald Reagan’s advisors manipulated the situation to their advantage, by feeding faulty technology back to the Russians in a decade-long Trojan Horse operation which fatally undermined Soviet science and technology. In February 1982, Vetrov was arrested for the murder of a bystander and the attempted murder of his mistress, KGB secretary Ludmilla Ochinkina.

This is the story of Viktor Bout, and he would become one of the most famous - or infamous - Russian businessmen in history. A former spy, he became the world’s most dangerous arms dealer, a man responsible for the deaths of millions worldwide. It’s a tale of greed and immorality that led to one of the most audacious undercover sting operations ever conducted.

In 1968, Dani Limor was recruited by Mossad. To this day, virtually all of Limor’s assignments remain classified. But their successes made him one Mossad’s top field agents. In 1977, the Israeli State officially recognised the heritage of an ancient tribe of 90,000 Jews, who were the descendants of those fleeing Jerusalem more than 2,500 years earlier. Now, they were 1,800 miles away, in an enclave of around 500 impoverished villages, in the northwest corner of Ethiopia, a country under the control of a pro-Communist military junta and funded by the Soviet Union. It became clear the Lost Tribe were not going to make it out of Ethiopia on their own. This is the story of how Mossad sent undercover agents into enemy territory to secretly repatriate thousands from the Lost Tribes of Israel. It’s one of the most daring rescue missions in the history of espionage.