For more than 10 years, Yoon Chae-ok has worked with her father to track down missing people, even ones who are dead. She’s used her sharp eye and agile survival skills throughout her rough childhood roaming across Manchuria and Shanghai with her father. Chae-ok meets Tae-sang while investigating her missing mother’s whereabouts. They strike a deal to assist each other in their respective missions and soon infiltrate Ongseong Hospital in search of clues.