When a long-forgotten college acquaintance sends Kate McMillan a friend request on a social media site, it seems harmless enough. But what follows sets off a chain of events, which puts her beloved family at risk and her very life in grave danger. Homicide Detective Mark Bartelli is part of a highly trained task force assigned to serve and protect. He's also deeply attracted to Kate. When a dangerous stalker kidnaps Kate, he vows to move heaven and earth to find her. THE EXCHANGE digs deep into the psyche of a deranged killer, who has a singular goal and one deadly obsession-Kate McMillan.