Former Naval Intelligence officer Thomas Magnum resigns his commission to become a private investigator on the north shore of Oahu, Hawaii. He lands a home in the guest house on the estate of millionaire author Robin Masters in exchange for testing the estate's security, but is forced to work under the strict and ever watchful eye of Jonathan Higgins, a former British Army soldier who serves as the estate manager, and constantly patrols the grounds with his two "lads" Zeus and Apollo, who are loyally trained Doberman Pinschers always ready to pounce on Magnum. Magnum makes good use of the perks that come with working on the estate, including driving Masters' sporty red 308 GTS Ferrari, Audi, and all-terrain Jimmy, as well as equipment such as high-end cameras and telescopes.