Tokyo is a city of towering buildings and teeming people. However, there used to be more than 100 castles in Tokyo. The chunks of stone, shrines and temples that you see without thinking may have been the remnants of these castles. Ayuri and Mine, two high school girls, will guide you around the castle ruins in Tokyo. Let's go on a little intellectual excursion that can be done in a limited amount of time after school or work!