Our protagonist, Cooper, played by Matthew McConaughey, is a hobo/engineer who finds a crash-landed space probe in a cornfield, which he returns to NASA in another cornfield. (Again, the whole Earth is cornfields.) Instead of asking how the fuck anyone has the resources to fund a space program, Cooper investigates what the probe is for and discovers that NASA has been searching for a new planet to populate and appears to have found one. They send a team to explore the planet (which includes a wise-cracking robot and Cooper, because he happened to be standing there), and the spacecraft dives through a wormhole, meets a race of "gravity beings," nearly gets sucked into a black hole, and then crash lands on Hoth II to discover that there's already a human settlement there and it's full of dead Chinese astronauts.
Here's where it gets a little weird.
Warner Bros./Paramount Pictures
"My God ... all of Earth has really been dead and Chinese all along."
The gang finds that the Chinese had sent a crew to the planet, which was wiped out by radiation from a nearby star. Realizing that the sun is about to rise and that they only have SPF 15 with them, they seek shelter in a cave covered by a special life form that absorbs the deadly radiation. The cave is also occupied by evil Chinese robots, who take the crew hostage and explain that the planet is going to be destroyed by another hitherto unknown black hole. The crew battles the robots and escapes with a gravity ray the Chinese had built with the intent of using it, somehow, to save humanity.