Japan has been invaded by the secret society "Black Devil," which aims to overthrow the government. Top hero Minemizu Mineta spends his days as a "professional hero" protecting the peace of the city from the enemy. However, following a certain incident, "Black Devil" has introduced a complete two-day weekend system. Consequently, the heroes also have to follow the same work schedule. Minemizu, a workaholic, is thrown into chaos by the "two blank days," but there is another reason for his confusion── (Source: Kodansha, translated)