The murder of her father sends a teenage tomboy on a mission of 'justice', which involves avenging her father's death. She recruits a tough old marshal, 'Rooster' Cogburn because he has 'true grit', and a reputation of getting the job done.
The four sons of Katie Elder reunite in their Hometown of Clearwater, Texas for their Mother's funeral, and discover that the family ranch is now in the hands of Morgan Hastings, the town's gunsmith.
Bumbling professor Ned Brainard accidentally invents flying rubber, or "Flubber", an incredible material that gains energy every time it strikes a hard surface. It allows for the invention of shoes that can allow jumps of amazing heights and enables a modified Model-T to fly. Unfortunately, no one is interested in the material except for Alonzo Hawk, a corrupt businessman who wants to steal the material for himself.