Xiao Di (Xu Jiao) is a poor boy who studies in an aristocratic school. He is honest and kind, but he is always bullied and ridiculed by rich kids. Xiao Di and his father (Zhou Xingchi) live in an abandoned old house. His father works hard every day to make him study well and make a name for himself in the future. On weekdays, Xiao Di is always very well behaved. Even if he is punished by the teacher for not having sports shoes in physical education class, he never blames his father. But this time, for a toy that everyone has, Xiao Di got angry with his father. Dad couldn't afford it, so he picked up a "ball" in the garbage dump for his son to play with. Who knows, this transparent little ball turned into a lively and cute space dog with super powers. Xiao Di was ecstatic and named him "Yangtze River No. 7". Xiao Di dreamed of using Qizai's superpowers to get 100 points, but he didn't expect that Qizai not only didn't help him, but made him get a zero. He secretly modified the report card and lied to his father. Dad was furious, Xiao Di ran away from home, and was angry to get good grades with his real ability to show his father. Unexpectedly, when Xiao Di was smiling and holding the report card, an accident happened at the construction site and his father fell down from the building...