Shadow Creek - Joy Fielding

In Brooklyn, Val waits for her soon-to-be ex-husband, Evan, to pick up their daughter, Brianne, for their Adirondacks excursion, along with his new fiance. When Evan phones to say he's been delayed, he asks Val to drive Brianne to the hotel. Val secretly hopes to learn more about his relationship with his fiance and to keep their daughter from forming too close a bond with the younger woman who might be her replacement.

After Evan confirms he is tied up at work, Val decides they'll all go camping and manages to persuade her reluctant companions. No one is yet aware of the brutal murders that have taken place only a few miles away. Eventually campers and killers collide, secrets are revealed, and lives are changed forever.