Following an alien invasion 60 years earlier which nearly destroyed the Earth, former Marine commander Jack Harper (Tom Cruise) is Tech 49, a drone mechanic and one of the last few humans stationed on the planet. Jack lives in a tower standing thousands of feet above the Earth where he and his colleague Victoria (Andrea Riseborough) are part of an operation to clean up the remaining forces of the invasion and extract the planet’s remaining resources. Jack and Victoria maintain contact with civilization via a video link with their commander, Sally (Melissa Leo) who is stationed in a large pyramid-shaped structure called ‘the Tet’, which is in a low Earth orbit. Jack and Victoria are due to join the rest of humanity on Saturn’s moon Titan in two weeks. Jack suffers from recurring dreams and flashbacks, featuring images of New York before the destruction and an unknown female. Assisting Jack in his cleanup work are weaponised “drones”, sophisticated airborne machines that scour the landscape to destroy the alien resistance, known as the Scavengers (or ‘Scavs’). The Scavengers are attempting to destroy the giant ‘Hydro-Rigs’, controlled by the Tet, which are removing water from the Earth.
Though only tasked with drone maintenance, Jack has in inquisitive nature and is keen on investigating the Earth’s barren landscape. He has created a small lodge in a secluded woodland area by a lake, where he relaxes and stores possessions he has collected, such as books, vinyl records and toys. Victoria does not share Jack’s interest in plants or objects from the Earth, instead wanting to complete the mission and leave for Titan.