Kyokutou Houreigai Tokubetsu Chiku (Far East Special District), sometimes known as the 24-ku, is an artificial island in Tokyo Bay (24th Ward). Ran, Kouki, and Shuuta, childhood friends who were born and reared there, come from various families, have different hobbies, and personalities, yet have always hung out together. Their relationship, however, alters dramatically as a result of a certain occurrence. The three friends happen to meet again at the incident's first anniversary commemoration, and their phones start ringing at the same time. The three will struggle to safeguard their beloved 24th Ward and the future of its inhabitants in their unique ways after receiving a phone call from a seemingly deceased friend encouraging them to "choose the future."