Stalin was dead, and Khrushchev was gone.

It was thirteen years since the great man who was both the one true son and father of the Soviet Union had been found on the bedroom floor of his dacha, semi-conscious and slowly dying from a brain haemorrhage. And it was five months since his liberal-minded but increasingly erratic successor had been forced into retirement by the ambitious troika of Aleksei Kosygin, Leonid Brezhnev, and Nikolai Podgorny.

The three new leaders were still struggling to calm a skittish nation and cement their grip on the vast power they’d claimed. Their preferred technique was taking every opportunity they could find to borrow from the collective memory of Stalin’s ultimate authority, which was why an unofficial week of mourning had been declared to mark the anniversary of his death.

It was a time of sombre, private reflection and the occasional public outburst. Cities, towns and villages across Russia had fallen near silent, and Moscow was no exception. Its streets were quiet. Its children were suddenly neither seen nor heard, forced to stay inside and watch the drifts of snow that had filled their parks and playgrounds all winter finally start to melt. And its adults shuffled soundlessly to the buses, trams, and trains that would take them to work and bring them home again. No one lingered outside after sunset as the temperature dropped back below freezing, not even the city’s sizeable but officially non-existent homeless population. Even they were off somewhere quietly drinking or crying to the memory of Stalin.

So, the resident of Zavodskoy Poyezd, 6, was entirely alone as they stepped out of the five-storey tenement at 8 p.m., gently closed the door behind them and made their way the short distance to Izmaylovskaya metro station.

Zavodskoy Poyezd, 6, with its flaking yellow plaster and scattered, unused balconies, was one of a hundred identical buildings all over Moscow. And its latest inhabitant, who had moved into one of its ground-floor apartments a week ago, looked like one of the thousands of workers who crossed the city every day, with their heavy coat wrapped round their body, thick gloves covering their hands, and a rabbit-fur hat pulled down low over their brow.

The metro rumbled along the edge of the vast, dark forest that separated Izmaylovo and Ivanovskoye districts, before plunging underground into the tunnel that took the M3 line into the heart of the Soviet capital.

The train only had one passenger, and only one pair of boots stepped down onto the tiled platform at Arbatskaya station and walked through its long, vaulted concourse hung with bronze chandeliers.

The streets around Arbatskaya were as deserted as everywhere else. It took the lone traveller ten minutes to reach their destination: a small mansion set back behind the Tchaikovsky Conservatory. And just another five to kill everyone inside.