"The Child Who Study 2" tells the story of Kaikai who was forced to separate from the stray dog "Xiaodan'er" when he went to school in the city. However, the friendship between this humane little dog and the kind little master transcended geographical barriers and was always connected by a thin telephone line. In order to let Xiaodan'er eat, Kaikai secretly picked up waste to collect phone bills for Xiaodan'er to make a long-distance call. After the Spring Festival, Kaikai and the new friends he met in the city finally welcomed Xiaodan'er who came to the city to visit relatives. Xiaodan'er learned to pick up waste, but unfortunately had a car accident. Kaikai read to the dying Xiaodan'er in tears... The film focuses on the vulnerable group of children of migrant workers, and portrays their survival and mental state with a strong sense of social responsibility.