Academy City was one of the world's foremost centers of education and scientific research. Its research standards were nearly a century ahead of those outside, and its technology was so advanced that the leak of any single achievement could cause an enormous impact on society.
To prevent these cutting-edge technologies from leaking and to protect the professors, teachers, students, and scholars within, Academy City had adopted a closed management system ever since its establishment.
Other than during the enrollment and graduation seasons, it was never open to the outside world. Even the various supplies it required were subject to strict restrictions when entering or leaving, and had to undergo layer upon layer of inspection to ensure there were no loopholes.