After leaving Naval Intelligence, the laid back Thomas Magnum III, struck a deal with the millionaire play boy author Robin Masters. Robin owned a rather large estate in Hawaii and Magnum moved into the guest house for free in exchange for running a series of security checks on the estate, property and vehicles including a fire engine red Ferrari. Magnum thought it was a good deal, until he met Jonathan Quayle Higgins, the keeper of the estate and Robin's guests. Higgins takes his job much too seriously for Magnum's taste and the two of them are at odds for the better part of the series. For the shows 8 years Magnum, with the help of this two best friends; T.C. the helicopter pilot and Rick the restaurant manager with tons of connections solved all manner of crimes all over the Hawaiian Islands and even the main land.

Magnum P.I. derived quite a bit of it’s popularity from the good looks of it’s star, Tom Selleck, the exotic Hawaiian locations, and the fire engine red Ferrari. At the time, it was unlike any action/detective show before it and still holds up today.