The story begins in Mokotów, a district of Warsaw, on 25th September 1944, the 56th day of the Warsaw Uprising. The Uprising will shortly fall after 63 days of fighting. After a decimated resurgent detachment makes a failed attempt to break away from the German troops’ encirclement, Zadra, the commander, orders them to get through the waste water piping to the city centre where the fighting is still going on.
The group moves through the dark, winding underground system which is half filled with water and excrement, whilst the Germans guard at the manholes to throw grenades. Although the group breaks down, Zadra believes that the entire detachment follows him – a conviction which is fuelled by Kula, the head of the company, who fears that the commander will turn back to look for his dispersed people.
Meanwhile the second lieutenant Mądry, a musician who accidentally got involved in the uprising, and Halinka, a young nurse in love with Mądry, are looking for a way out on their own. The badly injured Korab and Stokrotka, the liaison officer taking care of him, also get lost and reach a barred exit... Mądry, who cannot bear the gruesome wandering any more, exits through a manhole guarded by the Germans. Only the commander makes it safely to the surface, but when realizes that his people have remained in the canals, returns to the hell in which they are.