Black Hills by Nora Roberts

A summer at his grandparents’ South Dakota ranch is not eleven-year-old Cooper Sullivan’s idea of a good time. But things are a bit more bearable now that he’s discovered the neighbor girl, Lil Chance, and her homemade batting cage. Even horseback riding isn’t as awful as Coop thought it would be. Each year, with Coop’s annual summer visit, their friendship deepens from innocent games to stolen kisses, but there is one shared experience that will forever haunt them: the terrifying discovery of a hiker’s body.

As the seasons change and the years roll, Lil stays steadfast to her aspiration of becoming a wildlife biologist and protecting her family land, while Coop struggles with his father’s demand that he attend law school and join the family firm. Twelve years after they last walked together hand in hand, fate has brought them back to the Black Hills when the people and things they hold most dear need them most.

Coop recently left his fast-paced life as an investigator in New York to take care for his aging grandparents and the ranch he has come to call home. Though the memory of his touch still haunts her, Lil has let nothing stop her dream of opening the Chance Wildlife Refuge, but something … or someone … has been keeping a close watch. When small pranks and acts of destruction escalate into the heartless killing of Lil’s beloved cougar, recollections of an unsolved murder in these very hills have Coop springing to action to keep Lil safe.

Lil and Coop both know the natural dangers that lurk in the wild landscape of the Black Hills. Now they must work together to unearth a killer of twisted and unnatural instincts who has singled them out as prey.