The story of Mo Mo happened in a city, and people became interested because they were advised to save time. As a result, people have nothing but crazy jobs, and people become more and more indifferent. In fact, the "gentlemen in gray" who advise time are trying to control the world. They cheat people of their time, because time is life. One day, a little girl named Momo came to town. Men, women and children like to make friends with her. She helped Master Hora, who was in charge of managing human time, to fight those "gentlemen in gray", and finally regained the time and returned it to the residents of the city.