Summer vacation is coming. In order to ensure the enrollment rate, a private high school organizes the top 30 students in the third year of high school to go to the living hall for tutoring. The top Yan Zhirun, the introverted and shy Jin Shixi, the former swimming team leader Yin Nalai, and the naughty JK are all on the list. Although reluctant, this group of young men and women still came to school as scheduled. During this period, their mobile phones were confiscated, and they abandoned all selfish thoughts and moved towards the goal of university as required by the teacher. The tense and boring days continued, but the terrorist incidents occurred, which disturbed the children's nerves. It was during the evening self-study time that the body of the girl Yinglan suddenly fell from the ceiling, and then they heard incredible news from the radio: from now on, they will die one by one, and who will finally walk out of this horrible death school has become a problem they have to face...