Who Had Murder on Their Mind? In Marigold Mesa, New Mexico. Diane Phipps, P.I. investigates the poisoning of mining magnate Ethan Marlboro. Hired by his fiancée, Rosamond Santorini, Diane works with Detective Jim Diamond to find out whodunit, and the motive is missing. Ethan died shortly after Rusty Shores fell into an old shaft at Ethan's Apache Plume Turquoise Mine. Owner negligence cited. Oddly, no one claims Rusty's remains. Closest to the victim, Rocky, estate manager, liked his boss; Gloria, housekeeper, was grateful for her job; Tiny, museum curator, kept his object d'art safe; fiancée Rosamond wants answers. Could cryptic fellow investors be guilty? Maybe, his ex-girlfriend, Natalie? Why is Bill, the mine manager, also murdered? Questions rise. How did a missing gold nugget get into Rusty's pocket? Who sends Ethan one hundred dollar bills? Who had gifted Ethan a Hopi death Kachina doll? And what about that "eye for an eye" scripture? Finally, who had access to thallium? Ethan was social and death opportunities were plentiful. Diane persists and sorts through it all. Confronting the killer rivals her encounter with a rattlesnake in the barn. But she survives and triumphantly stamps "CASE CLOSED' on the Marlboro File.