A murder takes place on an evening in the pouring rain, and Cho Jung Hyun, who has just returned to her hometown after 12 years, realizes that Cho Jae Young, her beloved niece, has gone missing. Meanwhile, Choi Hyung In, the detective in charge of the murder case, finds out that there is a relationship between the missing girl and Cho Kyung Ho, the culprit who's been charged and imprisoned for committing the Saju Station Gas Terror Attack.

Hyung In and the police start the investigation to find Jae Young. Hyung In meets Jae Young's school friends and they tell him about a tape. Hyung In finally obtains the tape, but a creepy and weird sound comes out from the tape. Meanwhile, Jung Hyun also tries to find Jae Young on her own. At places she visits, she gets to see some strange patterns. She knows that she has seen the patterns before, but don't remember what they are.

Hyung In tries to find leads to Cho Jae Young's case by listening to the cassette tape where mysterious sounds are recorded. When a drug addict's body is found at the port, Hyung In realizes that this case is related to a drug ring. Meanwhile, Jung Hyun finds a video tape she watched with her high school friends. The content is so creepy and mysterious but it's even more strange that no one remembers watching it.