From Amazon.com Hardcover description:
In the trauma center of Atlanta’s busiest hospital, Sara Linton treats the city’s poor, wounded, and unlucky—and finds refuge from the tragedy that rocked her life in rural Grant County. Then, in one instant, Sara is thrust into a frantic police investigation, coming face-to-face with a tall driven detective and his quiet female partner…. In Undone, three unforgettable characters from Karin Slaughter’s New York Times bestselling novels Faithless and Fractured collide for the first time, entering an electrifying race against the clock—and a duel with unspeakable human evil.
In the backwoods of suburban Atlanta, where Sara’s patient was found, local police have set up their investigation. But Georgia Bureau of Investigation detective Will Trent doesn’t wait for the go-ahead from his boss—he plunges through police lines, through the brooding woods, and single-handedly exposes a hidden house of horror buried beneath the earth. Then he finds another victim.…
Wresting the case away from the local police chief, Will and his partner, Faith Mitchell—a woman keeping explosive secrets of her own—are called into a related investigation. Another woman—a smart, upscale, independent young mother—has been snatched. For the two cops out on the hunt, for the doctor trying to bring her patient back to life, the truth hits like a hammer: the killer’s torture chamber has been found, but the killer is still at work.