Sometime in the 21st century, a series of crop blights on Earth threatens humanity’s survival. Joseph Cooper, a widowed former NASA pilot, runs a farm with his father-in-law, son Tom, and daughter Murphy. Living in a post-truth society (Cooper is reprimanded at school for telling Murphy that the Apollo missions did indeed happen), Cooper encourages Murphy to carefully observe and record what she sees. They realize that a pattern of dust on the floor is created by gravity variations and are able to decode it as a set of geographic coordinates.
Cooper and Murphy use the coordinates to drive to a secret facility, where Cooper’s former professor, Dr. Brand, continues to operate NASA in secrecy. Brand reveals that a wormhole near Saturn opens a pathway to a distant galaxy with potentially habitable planets. Twelve volunteers travelled through it, each assessing a planet’s suitability as humanity’s new home. Volunteers Miller, Edmunds and Mann have sent back encouraging data from planets near a black hole called Gargantua. Brand recruits Cooper to pilot the spaceship Endurance, carrying 5,000 frozen embryos for a “Plan B”: to colonize a habitable planet to ensure humanity’s survival. The only option for the majority of mankind to survive is his continued work on a “Plan A” – a gravitational theory for propulsion that would allow a mass exodus from Earth. Cooper agrees to go, upsetting Murphy who feels abandoned.
Cooper’s crew consists of scientists Romilly, Doyle, Brand’s daughter Amelia, and robots TARS and CASE. The crew traverses the wormhole and sets out to investigate Miller’s planet, where time is severely dilated (one hour equals seven years on Earth). Landing in shallow water, they discover that Miller is dead, and that the planet is unsuitable as a colony due to giant waves travelling across the planet’s surface. Amelia retrieves Miller’s data just as a massive wave of water hits, killing Doyle and delaying their escape. After returning to Endurance, they determine that 23 years elapsed in ‘normal’ time.
On Earth, Murphy is now a scientist and has been assisting Dr. Brand with his research. On his deathbed, Brand admits to Murphy that he never considered Plan A feasible and that he always considered Plan B as the only plan. Murphy, believing the equations can be solved, continues working on a solution to Plan A, knowing she needs more data on gravitational singularities.