Set in the affluent San Diego County suburb of Coronado, Californa, Coronado 9 stars the ruggedly handsome Rod Cameron as Dan Adams, a former Naval Intelligence officer turned private detective. Using his wits as well as brawn, Adams takes on cases too hot for others to handle, which often involve wealthy and celebrated clients. Taking Adams from his base in Coronado to far-flung corners of the world in search of justice, including London, New Orleans and Honolulu on the Hawaiian Island of Oahu. Among the many guest stars who seek his help are Doug McClure, DeForest Kelley, Beverly Garland, Connie Hines, Sue Ann Langdon and Argentina Brunetti.

Interestingly, Coronado 9 refers to his telephone exchange, harking back to a simpler time when all telephones numbers had place name prefixes.