It's the summer of 1996 and school's out forever for Andy, her boyfriend Marcus, her best friend Peter, and Em. When Andy's alcoholic mother predicts the apocalypse, the four teenagers decide to see out the end of the world at a deserted manor house, the site of a historic unsolved mystery. There they meet David--charming and unreliable, he seems to have appeared out of nowhere. David presents an irresistible lure for both Andy and Peter and complicates the dynamics of their lifelong friendship. When the group learns that a diamond necklace, stolen fifty years ago, might still be somewhere on the manor grounds, the Game--half treasure hunt, half friendly deception--begins. But the Game becomes much bigger than the necklace, growing to encompass years of secrets, lies, and, ultimately, one terrible betrayal.