When Kakeru Diachi's unusual hobby of collecting rare juice cans leads him to accidentally try to drink a girl named Melon, whom he mistakes for a can, he enters a bizarre world where these 'Akikans'—girls who are special cans—battle each other to determine the superiority of steel or aluminum containers. As Kakeru gets entangled in this outlandish research project, he finds himself stuck with Melon, who requires carbon dioxide to survive. Matters escalate when his wealthy childhood friend Najimi acquires her own aluminum Akikan, adding a new layer of complexity to Kakeru's already complicated life.