When a woman vanishes without a trace, Detective Kim Soo-jin is assigned what appears to be a routine missing persons case. Instead, he encounters a presence that feels disturbingly too close—someone who knows more than they should, watches more than they admit, and blurs the line between victim and suspect. As the investigation deepens, Soo-jin is drawn into a psychological maze where identity fractures, obsession masquerades as devotion, and love becomes something dangerous. This is a dark, intimate thriller about control, trauma, and the terrifying pull between two people who should never have met.