The partners investigate mysteries and protect clients with the sometime help of photographer Cricket Blake (Connie Stevens), who also sings at the hotel's Shell Bar, and a ukulele-playing cab driver Kim Quisado (Poncie Ponce), who has connections throughout the islands.

Engineer turned detective Greg McKenzie (Grant Williams), joins the agency later on as a full partner, while hotel social director Philip Barton (Troy Donahue) lends a hand after Tracy Steele departs.

These were the granting of statehood to Hawaii, the advent of mass tourism to the new state brought about by the introduction of jetliners for commercial passenger flights, and the promotional efforts of Henry J. Kaiser, whose real-estate projects in Honolulu included building the hotel complex originally known as Kaiser's Hawaiian Village (later the Hilton Hawaiian Village Hotel).

The series regulars, who were shown during the opening credits, are listed below in the order in which they debuted during the show's four-year run.

All of the Warner Bros. detective shows of this era featured a musical interlude, generally performed by a series regular.