Wu Yun and Wu Shan are biological sisters. The 26-year-old sister Wu Yun is a slim beauty working in a big city. She is the top scorer in the local college entrance examination. She wants to go home to live but cannot save her face due to conflicts with her father. The 16-year-old sister Wu Shan is slightly fat and studies in school. Xi Zhongyou is an ordinary high school student with mediocre qualifications in all aspects. She likes watching anime and wants to develop her hobbies but does not receive support from her parents. She grew up under the protection of her family and is eager to break away from what she considers to be constraints and see the outside world. The two lived an ordinary life at their posts until they returned home during the Chinese New Year. When they woke up, they found that their bodies had changed. Wu Yun turned into Wu Shan, and Wu Shan turned into Wu Yun...