In the year 2025, because of the climate abnormality, Taipei's streets are very cold. Mufan, who is a male succubus child "Mabuu", came to this city secretly. According to the demon rules, you need to take the challenge of living in the human world for 13 weeks by yourself in order to turn into an adult succubus. But there are a lot of hard parts for a demon to live in the human world, like money and a place to call home. Thank god Mabuu looks almost the same as humans. They can also use magic to avoid some troubles. Working hard on part-time jobs for a living and for Mabuu's physiological needs of finding targets to absorb the essence. After meeting plenty of different people, what dramatic changes will come to Mufan's trial?