A middle school located deep in the countryside. There are approximately 860 students, and including the faculty, nearly 900 people live and work here. Although it is an isolated place surrounded only by mountains and fields, the school facilities are as excellent as those in the city. The students were living ordinary lives until one morning, everything changed when a mysterious system window appeared before all students and staff. The system commands the participants to create their own characters. While appearances can be customized freely, abilities cannot be chosen directly. Abilities are determined randomly by analyzing the participant's personality, values, thoughts, and subconscious. However, one can directly select one category among Combat, Magic, Reinforcement, Summoning, Mental, Support, or Special. The moment character creation is finished, the entire school is trapped in a massive barrier. The main gate, fences, windows, roof, and even the ground are all blocked, so no one can leave the school. All contact with the outside world is completely cut off. The system has only one goal. To survive until the very end. Participants engage in the game under the same conditions, regardless of whether they are students or teachers. The game is divided into combat time and rest time. During combat time, free combat and the use of abilities are allowed, and participants can be attacked. Conversely, during rest time, attacks are prohibited, and designated areas turn into safe zones. If the rules are broken, the system executes the offender immediately. As time passes, the safe zones gradually shrink, and various parts of the school are closed off. Initially, the entire vast school can be used, but eventually, only an extremely narrow space remains. Participants must constantly make choices regarding food, supplies, allies, betrayal, and survival. And then, the system reveals the final rule. Out of approximately 900 participants, only 18 people can leave the school. The game never ends until only 18 remain. From that day on, the ordinary rural middle school becomes a massive survival battlefield. Relationships like student, teacher, friend, senior, and junior lose their meaning, and everyone becomes a survivor and a competitor. Now, all that remains for them is to survive and get out of the school.