The opera's libretto borrows for the most part from the central part of Andrei Tarkovsky's screenplay, reduced and punctuated by ironically humorous philosophical inserts from the Strougatski brothers' book.

In an uchronistic present, Earth has been briefly visited by an extraterrestrial civilization. Deserted and sealed off by the military, the contact zone remains the site of deadly paranormal phenomena. It is said that a "Chamber" exists at the center of the zone, and that anyone who enters it will have their most heartfelt wish granted. An eminent scientist and a best-selling author pay a "stalker", a sort of mystical guide and great surveyor of the Zone, to guide them to the Chamber.

Stalker is a new kind of opera, tending to free itself from the traditional form of lyric theater in favor of a more fragmented form, a search for the occupation of space and time that places the spectator in a non-strictly frontal position, wandering about, and in an immersive sound flux.  
While Stalker is set in contrasting habitats alternately evoking the industrial world and nature, scenes will take place in intimate proximity, or on the contrary at a great distance, sometimes barely visible but always precisely audible thanks to a system of headphones with which each spectator will be equipped.