Magnum, P.I. (1980)

A supposed wealthy teenage ranch owner hires Magnum for $100,000 to stop a dangerous group of cattle rustlers on Hawaii's big island, that will soon force his ranch into bankruptcy if many more cattle are taken. But Magnum finds that his employer isn't quite all he makes out to be and will go to any extent to protect his cattle, and the neighbouring ranch owner implicated of being behind the cattle theft is a business partner of Robin Masters'...