Because Buzz feels guilty for stranding them on this planet, he volunteers to test the formula for their hyperspeed crystal fuel, which is difficult to get the mixture just right to keep it stable. Thanks to the effects of relativity, Buzz ends up skipping four years with each test flight. After multiple failed test flights, Buzz has ended up about 60 years in the future, at which point the crew has settled in to life on this planet and no longer desire to leave.In the meantime however, Buzz's companion robot, a cat named Sox, has figured out the correct formula. Stealing the test ship, Buzz and Sox end up another 22 years into the future after a successful test flight. At this point in time however, the planet is under siege by Zurg and his robot army.
Unlike the Toy Story version of Zurg, he's a giant mech suit that an older version of Buzz pilots. I really like the design, but aside from the head, he really doesn't resemble the Toy Story version of the character. At any rate, he explains to his younger self that when he landed after the successful hyperspeed flight, he was threatened with jail, so he took off on another flight, where he found this alien ship in the future, and then used up his hyperspeed crystal fuel time traveling back to this era. The time travel paradox here is a little confusing, but whatever. Zurg Buzz intends to change history by giving the hyperspeed crystal fuel to the stranded crew after they'd crashed, but younger Buzz in the meantime has gotten to know some of the descendance of the crew, who'd be erased from history, and refuses to help his older self. Young Buzz, with the help of the group of colonists he's met, manages to destroy Zurg's ship and hyperspeed crystal fuel, and are welcomed back to the colony as heroes.
In a post-credits scene, it's revealed Zurg is still alive in orbit.
It's a decent enough film in its own right, I enjoyed it for what it is. But the premise as being the movie that Andy saw in 1995 and inspired the Buzz Lightyear toys just doesn't work for me. It contradicts what little of a storyline they'd established for Buzz in Toy Story and Toy Story 2.