The nuclear submarine "Voronezh", having gone on a training cruise in our time, fails in 1942. The destruction of the German Arctic Fleet cannot affect the course of the Battle of Stalingrad? But the information brought by our contemporaries will make it possible to carry out the “Big Saturn”, an operation that has never been realized in our history to defeat not just Paulus’s army, but the entire southern wing of the German front. And people from 2012 will have to take part in battles, and simply live in a world that they considered history. And in the end, a completely different story and a different world will come out.