Rykov’s office wasn’t in the Lubyanka or the Kremlin. Befitting his department’s unusual status, Line Z was based in an anonymous four-storey white stucco building sandwiched between a hotel and a power plant on the northern edge of the island that hugged the sweeping curve of the Moskva River as it passed through the centre of Moscow. According to the row of signs that lined the arch leading from the street to a small courtyard, the building was home to the Moscow offices of several small Soviet industrial communes. But these were all covers. Line Z occupied the entire place.

Rykov had started his KGB career in its imposing headquarters on Lubyanka Square as the assistant to General Grigor Medev, the head of the scientific directorate. Rykov was just twenty-two when Medev had been killed in Stockholm five years ago as he tried to stop a Russian physicist called Irina Valera from defecting to the West. Rykov had kept the directorate running smoothly in the immediate aftermath of Medev’s death—so smoothly in fact that a number of its staff and scientists hadn’t realised that their chief was no longer issuing their orders. Some considered this a presumption of power that should have seen Rykov packed off to a gulag, but others saw something different. They saw potential. Rykov was transferred to Line Z.

The KGB was a multi-tentacled beast of directorates, departments, services and lines. The first chief directorate was so large it had been split into multiple numbered and lettered sections that covered every aspect of Soviet intelligence and security, from research and domestic surveillance to international operations. Each section was supposed to have a clear responsibility and remit. Directorate S dealt with illegals—the Soviet agents who operated around the globe without official cover or diplomatic protection—Directorate K oversaw counter-­intelligence, and the scientific directorate’s official designation was Directorate T.

Line Z, however, was an anomaly. Originally founded as an experiment in free rein, it had quietly but relentlessly evolved, combining elements from other sections to create a miniature, fully formed intelligence agency within the KGB. After Khrushchev’s retirement, it had caught Brezhnev’s eye and his blessing and backing had given Rykov protection, influence, and power.

Line Z worked globally, combined research, human and signals intelligence, and was rumoured to employ tactics even more violent than the KGB’s feared active measures and wet work units. All to achieve the section’s—and Rykov’s—singular aim of causing chaos in the West.