Galaxy Quest

Jason Nesmith, once the star of the sci-fi TV series "Galaxy Quest", now attends fan conventions and cashes in on his past fame. However, his co-stars have a different opinion of him, viewing him as arrogant and a laughing stock. Their lives change when they're approached by an alien race called Thermians, who have modeled their existence after the series. The Thermians ask Jason and his co-stars to help them, and they initially believe it's just another paying gig. But they soon learn they must portray their roles for real, without a happy ending, and face technical issues they didn't care about during filming.