In 2077, the human Jack Harper works with his companion Victoria "Vic" on the surveillance station Tech 49. Jack repairs drones and his memory was erased as part of the security process to stay on Earth, and he knows that Earth is completely depleted after sixty years of war against the alien invaders Scavengers "Scavs". The aliens have destroyed the moon and were defeated by nuclear weapons and the earthlings have moved to Jupiter's moon Titan since the planet was completely destroyed. Now Jack has to protect the power stations that use the ocean to supply energy to Titan fixing the drones. He also has recollections of a mysterious woman at the Empire State Building when Earth was habitable. Jack and Vic receive instructions from Sally (Melissa Leo), who is located on the space station Tet, and Vic is anxious to leave Earth in two weeks to join the survivors on Titan. However, Jack has a cabin in a secret place where he likes to stay alone. When the spacecraft Odyssey crashes on Earth, Jack witnesses the drones killing the human crew but he rescues a woman, Julia, who is the woman of his recollections. Julia and Jack recover the flight recorder but they are captured by the Scavengers. Soon they learn that the Scavs are actually a group of humans, who tell Jack that the invasion was a lie. Jack does not believe them, and they release Julia and Jack into the radiation zone to find the truth.