3 men enter The Zone, an abandoned area where the very fabric of reality has been fundamentally altered, in order to find a room of incredible power which may have the potential to change their lives, and possibly the world, forever.
The Zone: a place of unlimited possibilities and terrifying freedom, or so some say. The very substance of reality is changed there, twisted, so that those who enter might never leave, while others may find, at its heart, The Room, which is at the apex of all these changes. Something that can twist reality around it could perhaps be manipulated, shaping the world how the subject most deeply wants. If the rumors are true, The Room is where this will happen.
Three men enter the Zone in search of The Room. The first is an eponymous stalker, someone with experience in The Zone, able to find his way through and know The Zone's dangers. The Writer and The Professor (who remain anonymous; The Stalker prefers it that way) have hired him to guide them through The Zone, but its power is not limited to bending the fabric of space, and they all soon find that what they think they want, and what they realize they might get, are not necessarily related.
Novel vs. Film
Stalker is loosely based upon the novel Picnic by the Roadside, by prolific Russian writers Arkadi and Boris Strugatsky. In the novel, the nature of The Zone is in some ways much more explicitly stated, and the conclusions on the meaning of The Zone and its existence seem different than the film. The films proclamations are vague at best, maintaining some of this mysticism throughout the work and focusing instead of the characters and their conversations.
It could be argued that the film takes the basic themes of Roadside Picnic and explores them in different ways, but with the philosophical conclusions differing so strongly, it's difficult to say that the film and the book are closely related.
It may be interesting to note that a poem that is recited by The Stalker while the group is in the Zone is a verbatim recitation of one of Tarkovsky's brother Arseny's own poems featured in Andrei's earlier film, The Mirror.
References in Popular Culture
The video game series S.T.A.L.K.E.R. makes many direct references to this film, including having anomalies and altered habitability in seemingly normal surroundings.