Test pilot Tuck Pendleton volunteers to test a special vessel for a miniaturization experiment. Accidentally injected into a neurotic hypochondriac, Jack Putter, Tuck must convince Jack to find his ex-girlfriend, Lydia Maxwell, to help him extract Tuck and his ship and re-enlarge them before his oxygen runs out.
After policeman Frank Dooley is framed for theft and loses his job on the force, he joins a security guard agency and teams up with inept former defense lawyer Norman Kane. When the two botch a job guarding a local warehouse, they begin to uncover corruption within the company and their union.
Sheldon Bart (Fred Ward) is a drifter, and a small-time con man. He meets his old friend, Brother Bud (Harry Dean Stanton), a big-time con man into faith healing and fencing stolen cars, at his revival tent outside a small town. While he's helping Brother Bud, he falls in love with Arlene (Cindy Williams), a local supermarket clerk who believes in UFOs and is deeply religious and deeply lonely. When Arlene has a vision of a coming UFO, everyone deals with it in their own way.