Lin is a Shut, destined to a life of undying love towards one person. Do-Sung is a Destroy, always on edge to hide the violent outbursts they're known for. In this world, it's not just the genetic, but also the psychological traits that distinguish them. Just as Lin is coldly rejected by Do-Sung, a string of horrific murders threatens their lives and the investigation creeps ever closer. Everyone has a secret in this society of differences, but can Lin turn Do-Sung around? The countdown begins in this gripping romance thriller.