The capture of the German city of Poznan opens a path for Soviet troops to Berlin. But the fascists have no intention of surrendering. They defend to the last, turning the city into an impregnable fortress with concrete fortifications and unprecedented firepower. At the tip of our assault, a battalion of Major Prokhor Burmistrov is in action. The fighters claim strategic ground from the enemy meter by meter until they reach a labyrinth of ancient stone walls. But stopping now means sabotaging the offensive. Burmistrov dares a desperate step: if it’s impossible to go around these walls, then it’s necessary to go… through them…