With help from a young woman with synesthesia, a cop who lost his sense of pain tracks down the serial killer who brought tragedy to both their lives.
The Barcode Killer abducts Cho-rim in order to lure Mu-gak into a deadly trap, but Cho-rim leaves behind a clue that could save his life.
The Barcode Killer makes a run for it. Cho-rim remembers more about her parents and the day of her accident. A romantic gesture backfires on Mu-gak.
When the police are unable to find the secret room where Yeom Mi is being held, Cho-rim contacts the Barcode Killer and volunteers to take her place.
Cho-rim reveals her special ability to the entire Violent Crimes Unit. The Barcode Killer uses the witness's old school friends to lure her into a trap.
Cho-rim manages to escape from the Barcode killer, who steals a photo from her father's home address in order to identify her.
Mu-gak snoops in Yeom Mi's office and learns why she took him off the case. The Barcode Killer visits Cho-rim's dad to find out who the witness is.
Yeom Mi follows her hunch about Cho-rim, who has a flashback to the moment of her accident. The misplaced confession letter is found among some books.
Mu-gak lures the Barcode Killer using fake medical records and a decoy Choi Eun-seol. Yeom Mi creates a police sketch of the woman Cho-rim remembers.
Mu-gak is rushed to the hospital, where the police set a trap for his attacker. The Barcode Killer decodes his last victim's cryptic final message.
The Barcode Killer places the next body so it will be found, and covers his tracks. Cho-rim's friend Ma Ae-ri is accused of stealing from her employer.
A confession letter is written and stored. Ju Ma-ri's journals are discovered. Mu-gak figures out what the barcodes on the victims' bodies signify.
When a strangled chef falls off a roof, Kwon Jae-hui becomes a suspect, but a scent leads Cho-rim elsewhere. Mu-gak learns why Baek-gyeong went to Jeju.
A new barcoded body is found, but Lt. Yeom Mi suspects it's a copycat killer's work. An accidental injury brings Cho-rim to Dr. Cheon Baek-gyeong.
Cho-rim leads Mu-gak to a body in the river, and is later followed. Mu-gak reveals to Cho-rim how he lost his sense of pain, taste and smell.
Choi Mu-gak agrees to help Oh Cho-rim with her comedy skit in exchange for assistance on a case that could earn him a spot in the Violent Crimes Unit.
After her parents are murdered, a young woman awakens from a coma with total amnesia, and crosses paths with a cop who suffered a loss of his own.
With help from a young woman with synesthesia, a cop who lost his sense of pain tracks down the serial killer who brought tragedy to both their lives.
as Choi Mu-gak
as Oh Cho-rim
