An anonymous tip leads the police to a hotel pool party; Do Jeong-u cracks the code to learn the location of the fourth murder.
Former FBI profiler Jamie Leighton joins the task force; Lee Ji-uk secretly tails a victim to capture footage and nail an exclusive.
When Son Min-ho is named as the next target, the team is briefed on the White Night Village tragedy; Min-ho suspects a survivor as the culprit.
After Jeong-u reveals he's from White Night Village, Jamie opens up about her dark childhood; the task force keeps a close eye on Min-ho's home.
Jeong-u is put in charge of Min-ho's protection; a news segment about the police officer's heroic rescue helps Jamie piece together key clues.
Gong Hye-won catches the criminal red-handed at the scene, but is perplexed when prosecution takes over the case; Jamie seeks answers about her surgery.
Namgoong Min
Do Jung-woo
Kim Seol-hyun
Gong Hye-won
Lee Chung-ah
Jamie Leighton
Yoon Sun-woo
Moon Jae-woong
Kim Chang-wan
Gong Il-do