In 1962 Taiwan during the White Terror martial law period, Fang Ray Shin, a female student at the hillside Greenwood High School is attending counselling with teacher Mr. Chang, and they gradually fall in love. It was a dangerous period where sensitive books were banned and free speech were restricted, but Mr. Chang secretly organised a study group for banned books, together with fellow teacher Miss Yin and male student Wei Chong Ting. One day, Mr. Chang disappears. Ray Shin and Chong Ting then wake up in the middle of night in their empty school and are trapped inside. They must now escape the school and find their missing teacher. The school building has become a place where demons rampage and they will have to confront the truth and dark historic past in their school. Can they survive?