A stranger named Jun Woo approaches Jeong Yun and tells her that he could see her future of being stabbed to death in 6 hours on her 30th birthday. She doubts him but follows him anyway to find out who the murderer would be to avoid her death. However, as they go deeper into the case, she realises Jun Woo is the key to recent serial killings. Now she is left with the question of whether he is really saving her life or is the devil who is trying to set her up.