A mysterious high school mass murder that occurred three years ago remains unsolved. The only survivor of the incident, Gong Neum, is drawn to the Devil's Forest cabin by the shaman, Yeo Sunji. Yeo Sunji's true motive is to use Gong Neum to appease the vengeful spirits of the children who were brutally killed three years ago. As Gong Neum faces hidden memories and buried truths, the time for retribution finally arrives.