Guardian of the Lost Colony

The setting's an oasis on the upper Sonoran Desert. There are rattlesnakes pouncing, tarantulas threatening and hawks divebombing the residents of the Lost Colony. And that's the easy stuff.
The talking mice of the colony also have to contend with a would-be scientist who's losing it, whose allies wear jack boots and buzz them with helicopters. Angus Brownfield's latest addition to the Mustt Adventures, Guardian of the Lost Colony, is an Elmore Leonard western where the good guys wear bristling whiskers instead of white hats.
Dorothy, heroine of the first two Mustt Adventures, has passed on, but her feisty brother, Brack Mustt, has survived incarceration by Jason Ramback and made his way to the oasis that would be Shangri-La, if only humans would stay consistently civilized.
Gavin MacDonald, who teamed up with Dorothy in The Scrivener's Tale, has good intentions but looks like trouble to the fiery Matilde Abandolao, who thinks it's her destiny to prevent the outside world's interference with her cherished mice. Before she'll let harm come to them, she'll shoot Gavin and try to shoot down the CIA's helicopter.
How do the mice of the Lost Colony shape a future that's secure yet independent in proper measure? Flee? Hunker down? Eschew humans altogether?
You'll think you've got it figured out when Gavin and Matilde form a loving partnership, but you have to know, talking mice have been building a culture of their own, and you're about to learn how they plan to live in it.