Jerry Lewis is Kreton, a childish alien who, against his teacher's will leaves his planet to visit the Earth, and lands in the backyard of a famous television journalist who doesn't believe in U.F.O's and aliens. Wanting to study humans but not able to fully understand them, Kreton makes a mess out of it, generating a lot of comic situations.

Police Lt. Diamond is told to close his surveillance of suspected mob boss Mr. Brown because it's costing the department too much money with no results. Diamond makes one last attempt to uncover evidence against Brown by going to Brown's girlfriend, Susan Lowell.

The wife of marshal Matt Morgan is raped and murdered. The killers leave behind a distinctive saddle, that Morgan recognises as belonging to his old friend Craig Belden, now cattle baron in the town of Gun Hill. Belden is sympathetic, until it transpires that one of the murderers is his own son Rick, whom he refuses to hand over. Morgan is determined to capture Rick and take him away by the 9.00 train; but he is trapped in the town alone, with Belden and all his men now looking to kill him.

Texan rancher Bick Benedict visits a Maryland farm to buy a prize horse. Whilst there he meets and falls in love with the owner's daughter Leslie, they are married immediately and return to his ranch. The story of their family and its rivalry with cowboy and (later oil tycoon) Jett Rink unfolds across two generations.