When Kristin Chapman agrees to let her husband, Richard, host his brother's bachelor party, she expects a certain amount of debauchery. She brings their young daughter to Manhattan for the evening, leaving her Westchester home to the men and their hired entertainment. What she does not expect is this: bacchanalian drunkenness, her husband sharing a dangerously intimate moment in the guest room, and two women stabbing and killing their Russian bodyguards before driving off into the night. In the aftermath, Kristin and Richard's life rapidly spirals into nightmare. The police throw them out of their home, now a crime scene, Richard's investment banking firm puts him on indefinite leave, and Kristin is unsure if she can forgive her husband for the moment he shared with a dark-haired girl in the guest room. But the dark-haired girl, Alexandra, faces a much graver danger. In one breathless, violent night, she is free, running to escape the police who will arrest her and the gangsters who will kill her in a heartbeat.