By the river beach, the elderly couple of the Shi family unexpectedly rescue the injured spiritual flood dragon Yin Chuan inside a wooden chest. Yin Chuan, grateful for their kindness, recognizes the two as his father and mother. To win the hand of the kind maiden Su Qinghe, he takes up Su's father's three difficult challenges: in three days repairing the cliff stone bridge, in two days completing the green-brick residence, and in three years improving the saline-alkali wasteland. Yin Chuan does not rely on might or arrogance, inviting all the villagers to labor with one heart, repairing the bridge for public convenience, building a house to settle down, and improving the farmland to benefit the neighboring villagers. Su Qinghe sees through Yin Chuan's benevolent and kind original nature, not fearing him because of his non-human true body. The two cross boundaries of race, hand in hand going together toward a plain and warm mortal life.