As a fresh graduate of the police academy, Qian Xiaotian's greatest dream is to join the criminal investigation department and become a detective. But by a twist of fate, he is accepted into the Traffic Corps PDU with top scores, where he becomes an intern as a dog trainer and even gets assigned a proud police dog named "Dumpling". Thus, Qian Xiaotian, whose dream has been shattered, begins his painful professional life at the PDU, where every day is a battle against heaven, earth, and dogs. As Qian Xiaotian dives deeper into his job, he finds a new understanding of the dog training profession. He sees old age, illness, and death. He passes through trials and tribulations. He learns to persevere or give up. Joy and sorrow are intertwined. The relationship between police dogs and the trainers is not only a story between human beings and dogs but also about true camaraderie. In the end, Qian Xiaotian and his dog eventually become the pride and joy of the PDU.