Akira Shibue, who attends the art museum Senboku Gakuen, will participate in a summer joint camp between her swimming club and track and field club. She is the director of the swimming club and the student council president, Ashinari. Her childhood friend Kiyohara Rio, who belongs to her track and field club, Suda and his friends and friends who participated in the training camp are having a tough and fun time. Her feelings for the person she admires, her childhood friend and her best friend's love affair, and her vague anxieties and dreams about the future when she talks with her friends. A mundane youthful moment that flows on a summer day. It flowed strongly, vividly, but gently, and was supposed to be an unforgettable memory. on the other hand-- A crazy epidemic that breeds and spreads unknowingly and commits everything. Infected people who are gradually deprived of their reason and become violent. The shadows of the end-of-life calamities swarmed around them, urging them to overrun.