This movie is a satirical comedy which pokes fun at the influence shows like Star Trek have had on their audience. The movie begins with the cast members of a sci-fi television series called Galaxy Quest appearing at conventions and grand openings. The show has been over for eighteen years, but is still being shown in reruns and still has many loyal fans (and fanatics). Apparently the main actors of the series have never been able to land a steady new role therefore must rely on the fame from the old hit series to make a living. Over the years a great deal of jealousy and infighting has come between the members of the crew, especially between the Commander and the others due to the enormous ego of the Commander.
 Things begin to get interesting when an alien race known as the Thermians arrive to ask the Commander for help. The Thermians are a very smart, but at the same time very naive race. They have intercepted transmissions of the show and believe them to be historical documents. They have built working copies of the space ship, all the weapons, and have even modeled their culture around the show's characters. They are now threatened with genocide at the hands of General Sarris and his army, and the Thermians believe their only hope is for their hero, Commander Peter Quincy Taggart, to lead them to victory against General Sarris. The Commander's ego gets a real boost out of this and before he and his crew of actors know it, he has them in real danger in a real battle in space.
 Although this movie gets off to a slow start it makes up for it after the battle really starts, which is about half way through the movie, and the second meeting with General Sarris. Also if you get this movie on DVD be sure to check out the extras on the DVD, like the interviews and the outtakes.