Little Man is a divine dog from the heavenly realm, trained by Master Shan Yi from the Stone Buddha Monastery. After arriving at the Stone Buddha Hall, Little Man acts according to the master's permission in everything, and is called a 'coward' by his fellow practitioner Jin Ba, but Little Man does not care at all. One day, the Jade Rabbit came to the Stone Buddha Hall to steal a scripture, and was discovered by Jin Ba and Little Man. Jin Ba wanted to cross the boundary gate to chase the Jade Rabbit, but because the master had warned him never to approach the boundary gate, Little Man blocked Jin Ba's way. During their argument and struggle, Little Man accidentally fell into the boundary gate and plummeted to the mortal realm. Tong Xiaoxiao is an elementary school student in the mortal realm who, out of fear of trying, always fails to meet the standards in physical education and is publicly called a 'coward' by some classmates. When these two 'cowards' meet in the mortal realm, some magical things happen. After witnessing the magic key of Little Man, Tong Xiaoxiao hopes to use the key to help himself pass the physical education class. Little Man advises Tong Xiaoxiao that he must change himself and cannot rely on external forces. Tong Xiaoxiao successfully resolves the crisis with his classmates. At this moment, the Jade Rabbit discovers the key in Tong Xiaoxiao's hand and orders his subordinates to capture Little Man and seize the key. Later, with the help of Tong Xiaoxiao and his classmates, Little Man defeats the Jade Rabbit and successfully returns to the Stone Buddha Monastery.