Foiling drug trafficking in Colorado’s high country keeps Deputy Mattie Lou Cobb and Robo, her K9 partner, on the run. But when Robo alerts to another, more ominous, scent—the remains of a teenage girl— the stakes get higher. The tightly plotted puzzle, which also involves a local vet, his daughter and a town’s dark secrets, scrolls out from there. Mizushima not only has a deft touch with dialogue, she’s also done her homework on the training and handling of law-enforcement dogs. This debut novel, with its bright, dedicated human and canine protagonists, is a promising first entry in what we hope becomes a series.