The titular "Spaceballs" are a bunch of unscrupulous nutjobs intent on stealing the air of the beautiful world of Druidia to save their own over used homeworld. To this end they capture a druish princess who can only be rescued by a space bum called Lone Star and his scruffy man dog pal, Barf. But the evil Dark Helmet is not easily defeated. Puerile and fun, this purports to be a Star Wars spoof, but pulls in many other sources along the way including Alien (complete with John Hurt) and Star Trek.