Awaiting the birth of his first kittens, feline P. I. Joe Grey, his companion Dulcie, and their furry sleuthing pals must unmask a killer preying on some of the most vulnerable citizens in the charming California coastal community of Molena Point.

For Joe Grey and Dulcie, life is a bittersweet mix of endings and beginnings. While they joyfully await their first litter, they are also sad for their friend, the old yellow cat Misto, whose time on earth is drawing to an end. But Misto tells them an exciting future awaits: among the litter will be a little calico returned from the distant past who will be born with the same ancient markings, and the adventurous spirit of Joe Grey.

While the proud parents await the birth of their babies, their humans have their hands full with projects of their own. Kate Osborne has bought the old Pamillon estate and Ryan Flannery is building a new cat shelter as part of their volunteer rescue project. The criminals are busy, too. The Molena Point PD has stepped up patrols to apprehend a mugger attacking the local elderly. The case becomes a homicide when one of the victims dies, leaving everyone in the town—including Joe and Grey and his furry sleuthing companions—on edge, just when the kittens are about to arrive. When Dulcie gives birth, her little calico is just as Misto predicted, as if she has come back to the world from mythic ancient times.

But the celebrations will have to wait. A murderer is on the loose—and neither young nor old is safe until the culprit is found.