Hume Cronyn and Jessica Tandy are among the impoverished residents of a slum tenement threatened with demolition by evil land developers. Only a miracle can save Cronyn, Tandy, and their friends -- and that miracle manifests itself in the form of a "family" of extraterrestrial flying saucers, who need the electricity provided by the tenement to survive. The grateful humanized spaceships repay their earthbound hosts by doing battle with the villains' henchmen. When the building is engulfed in flames, all seems lost, but the aliens have a few more tricks up their metallic sleeves.