South Korea, 2009. A few days before their wedding, veterinarian Jang Mun-ho (Lee Sun-kyun) and his fiancee Kang Seon-yeong (Kim Min-hee (actress, born 1982)) pull over for coffee at a motorway rest stop on the way to visiting his parents in Andong, southeast of Seoul. However, when Mun-ho returns to the car, Seon-yeong has disappeared and is not reachable on her mobile phone. All he can find is a hairpin in the rest stop's toilet. From the mess at her flat in Seoul, it looks as if there has been a break-in. Mystified, Mun-ho then learns from a banker friend, Dong-woo (Kim Min-jae), that Seon-yeong had earlier applied for a bank account but had been turned down when it was discovered she had a history of personal bankruptcy dating back to 2007. Investigating her debt history, Mun-ho finds she had been using someone else's name and identity. He persuades his cousin, Kim Jong-geun (Jo Sung-ha), a former police detective sacked for taking bribes, to help find her. Examining her flat, Jong-geun finds she left no fingerprints, had no friends and claimed her mother died two years ago. It then turns out that the woman (Cha Soo-yeon) whose identity she assumed two years ago had a debt history and has since vanished. Visiting Seon-yeong's hometown, Jong-geun hears rumors she killed her mother for her insurance money. Seon-yeong's real name is, in fact, Cha Gyeong-seon, and Jong-geun and Mun-ho realize she is now looking to take on another woman's identity. They think they know her possible target.