Xia Tian and her group go on a trip to relax and unwind, only to encounter a young girl blocking their path and pleading for help. In their effort to rescue her, they are entangled in a disaster where mutated rats begin attacking humans.

Ji Miaomiao, a young woman just starting her career, is betrayed by a friend and left with a mountain of debt. While fleeing from ruthless debt collectors, she accidentally falls from a building. On the brink of death, a mysterious figure transforms her into a cat. By a twist of fate, she ends up being adopted—by none other than her own boss, Lu Chengze. Thus begins her strange and magical 100-day life... as a cat.