Amanda and Clay head out to a remote corner of Long Island expecting a vacation: a quiet reprieve from life in New York City, quality time with their teenage son and daughter, and a taste of the good life in the luxurious home they've rented for the week. But a late-night knock on the door breaks the spell. Ruth and G. H. are an older couple-it's their house, and they've arrived in a panic. They bring the news that a sudden blackout has swept the city. But in this rural area-with the TV and internet now down, and no cell phone service-it's hard to know what to believe. Should Amanda and Clay trust this couple-and vice versa? Is the vacation home, isolated from civilization, a truly safe place for their families? And are they safe from one other?