Lil Chance and Cooper Sullivan have been friends since their childhood summers in South Dakota. They fall in love one summer before they go off in their separate directions, he to become a New York City cop and she to become a wildlife biologist. They meet again ten years later when Lil and her Wildlife Refuge are in danger from a deranged stalker.
Roberts follows one of her formulas (previously seen in The Reef, and River's End) where the couple fall in love very young, he breaks her heart (usually for her own good) and then they reconnect when they're both older, wiser, and more bitter. Of course they fall in love again, but he has to apologize, grovel, and win her back first.
I thought the mystery was a bit lacking in this one, once you realize who the killer is, he seems so beneath them. But I did enjoy the Deadwood setting.