In the latest installment of this beloved series, canine PI Chet bites off more than he can chew when he and human partner, Bernie, take on a cryptic case in the Arizona desert.

The desert hides many secrets. The Little Detective Agency, consisting of Chet the dog and his human partner, Bernie Little, are good at digging up secrets—Chet especially—but now they face their most baffling case yet. Nothing in their career has prepared them for competing paleontologists, the viciousness of academic infighting, or the slow-motion wiliness of a giant desert tortoise long thought to be extinct.

Chet and Bernie are about to be hired by Maya Lakey, a legendary paleontologist nearing the end of her career. But she never gets to tell them why. That's not something Chet and Bernie can live with so they start looking into Maya's life. Questions arise right away. Were two falls, many years apart and both ruled accidental, connected? Who paid for a clifftop safety fence and why? What does a non-speaking, dog-loving survivor know, and can Chet somehow learn what's in his memory?

No one is making it easy for the duo. There's a rogue sheriff who knows more than she lets on, a retired cop with a collection of gleaming Porsches, and evidence of someone high up pulling the strings. In the middle of all this Bernie and his girlfriend Weatherly are trying to plan their wedding, and everyone is angling for an invite, including Dippy, a perp who specializes in stealing wedding cakes and holding them for ransom, and Robespierre, an ancient desert hippie who may have all the answers.