Lin is a Shut, fated for a life of undying love directed at a single person. Dosung is a Destroy, constantly on edge to conceal the violent outbursts for which they are known. In this world, it is not only genetic but also psychological traits that set them apart. Just as Lin is coldly rejected by Dosung, a series of horrific murders threatens their lives, and the investigation draws ever closer. Everyone harbors a secret in this society of differences, but can Lin change Dosung? The countdown begins in this gripping romance thriller.