Pastor Park is head of a religious investigation center that exposes cults and cult leaders. While looking into a suspicious new religion called Deer Mount, he slowly uncovers clues that connect this cult to a series of mysterious cases of missing teenage girls when a body is found inside a damaged tunnel beams. He begins to uncover dark secrets surrounding this cult and its enforcer Na-han. Pastor Park works to expose suspicious religious groups. He's hired to look into the cult group Deer Mount. Meanwhile, Police Captain Hwang investigates a murder case and the main suspect is a member of the Deer Mount cult.