Near a gray and unnamed city is the Zone, a place guarded by barbed wire and soldiers, and where the normal laws of physics are victim to frequent anomalies. A stalker guides two men into the Zone, specifically to an area in which deep-seated desires are granted.

An anthology film presenting remakes of three episodes from the "Twilight Zone" TV series—"Kick the Can", "It's a Good Life" and "Nightmare at 20,000 Feet"—and one original story, "Time Out."

Drawing heavily from Arkady and Boris Strugatsky's 1971 novella 'Piknik na obochine' ('Roadside Picnic') as well as Andrei Tarkovsky's 1979 film adaptation ('Stalker'), 'Tretya planeta' tells the story of a father seeking a cure for his ill daughter by venturing into an area known only as "The Zone" to request help from the mysterious healers that dwell within its forbidden borders.