The story is set in this battle, showcasing the story of a famous sniper. The movie is based on a book, Enemy at the Gates: The Battle for Stalingrad, written in 1973 by the author William Craig. One of the most famous soldiers from this battle is Vasily Zaytsev (Wikipedia link) (Vassili Zaitsev - His book), a solider who became a sniper and was responsible for the deaths of more than 400 German soldiers. He was a much decorated soldier who did most of his killing in a 2 week period in November-December 1942, a period in which the fighting was in the city, at eyeball level. The fight in the city cause destruction of large parts of the city. The movie showcases a fight between Vasily and a German sniper, a major with whom he had a running battle which has to result in the death of one of them.
The movies tells the story during the war of a Vassili Zaitsev (acted by Jude Law), a shepherd who like many others is now a soldier in the Red Army. With the quest to push back the Germans and prevent the Germans from crossing the line of Stalingrad, the defense of Stalingrad was a critical point. Army units were pushed into this battle, and Vassili was one of the fighters there, finding himself in the company of a political commissar Danilov (played splendidly by Joseph Fiennes). In one such push, Danilov sees impressive shooting by Vassili and works on the visiting Nikita Khrushchev to portray Vassili as a Soviet hero; the people need a hero and Vassili would be such a hero. He is transferred to the sniper school. And in a interesting touch, both Vassili and Danilov become interested in a female militia soldier, Tania (played by Rachel Weissz). This rivalry between them is going to strain their friendship.
The snipers play an important role in defeating the Germans (having an effective sniper is devastating to morale, since it means that a soldier is afraid of getting killed any instant), and the Germans bring in a senior sniper, major Erwin Koing (played to great effect by Ed Harris). He is also a very effective sniper and almost traps Vassili, killing 2 of his fellow snipers. Even a sniper sent to kill Erwin is killed, which makes Khrushchev impatient to get rid of Erwin.
A small boy, Sacha, becomes a helper to Konig, to get information about the whereabouts of the Major so that Vassili could trap him and kill him, but it is not easy. The Major is becoming suspicious of Sacha, and in the meantime the obvious relationship between Vassili and Tania is causing jealousy in Danilov. What happens next ?