22nd century. Artificial intelligence is integrated into all industries, the Moon and Mars are colonised, human-populated satellites orbit Neptune, the most distant planet in the solar system. A new Tower of Babel is being built on Earth. It's an antenna, the end of which reaches into outer space, to search for intelligent alien life. The team building this giant structure is led by Roy McBride (Brad Pitt).
He became an astronaut thanks to his father (Tommy Lee Jones), who was the commander of the Lima Project research expedition. She too was tasked with searching for advanced alien life and disappeared somewhere in deep space twenty years ago. Now Earth is hit by a series of unexpected disasters that will affect the construction of the giant antenna. US intelligence agencies believe that Roy's father is still alive and that the threat to Earth is linked to explosions occurring near the planet Neptune and linked to the Lima project.
Roy is sent on a space mission that takes him across the Moon and Mars to the outer edge of the solar system to find his father. But his journey uncovers a secret that questions the very nature of human existence and its place in the universe...