They Fought for Their Motherland

Why does a rearguard hold a bridgehead on the Don in July 1942 while the rest of the army crosses behind it? Sergei Bondarchuk, adapting Mikhail Sholokhov's novel, follows a platoon with Pyotr Lopakhin (Vasiliy Shukshin) and Nikolay Strel'tsov (Vyacheslav Tikhonov) as it falls back through the countryside before the German drive on Stalingrad. The soldiers keep walking, and their fear and their companionship go with them.