Our time. The pride of the Northern Fleet, the Russian nuclear submarine Dmitry Novgorodsky, is leaving for duty in the Middle Atlantic. A hike would be just like a hike, if not for the presence on board of a military expert with cunning equipment. The high command ordered a secret experiment to be carried out at sea. And they spent... The cold summer of 1942, at the height of the Second World War. There's no way you can go back. No matter which shore you approach, there are strangers everywhere. The main thing is that our own Soviets will not stand on ceremony with the crew. And the nuclear submarine "Dmitry Novgorodsky" involuntarily becomes a kind of "Nautilus", a homeless sea wanderer. But it is difficult to remain indifferent when your grandfathers and great-grandfathers are fighting and dying nearby. And a requiem for the PQ-17 caravan is about to sound nearby. The crew decides to begin military operations against the fascist reptiles. A nuclear reactor providing an almost unlimited cruising range and complete autonomy, excellent acoustic equipment, Vodopad torpedo rockets, the latest MANPADS - all this makes the Dmitry Novgorodsky a formidable weapon in the fight against the fleet of the Third Reich. The submarine cruiser begins a new combat campaign. Or rather, it continues what it started...