Veterinarian Hao Yun (played by Chen He) accidentally discovered the existence of transformers in this world because of a cat breeding accident. The Animal Management Bureau took Hao Yun away, but they couldn't erase his memory by various means, so they had to force him to join the Animal Management Bureau. From then on, Hao Yun and the extremely powerful Wu Aiai (played by Wang Ziwen) formed a partnership and began to deal with animal cases one after another... opening up the story of a huge and mysterious urban elf world.