Two donkeys wander into a fairyland and meet a chestnut mare, a fairy who was banished for breaking heavenly laws and sentenced to atone by eating grass.
The stubborn donkey and the chestnut mare fall in love, but another hardheaded donkey falls in love with the first donkey. Later, following an immortal's guidance, they devote themselves to cultivation. Just as they are about to become immortals, Erlang Shen's celestial hound knocks them down to the mortal realm. Though they take human form, they still retain their donkey nature. They suffer every kind of humiliation in the human world and make donkeys of themselves at every turn. Just as the stubborn donkey is on the brink of death, a little boy saves him. The child is none other than the son of the stubborn donkey and the chestnut mare: Ma Yunfei.
When the immortal gives the two donkeys a chance to choose between being human and being donkeys, they choose the latter without hesitation. Pressing their bodies together and swaying their bottoms, they happily wander off toward the mountains...
