Cui Lan, a herb-gathering woman, risks her life to save a white dragon about to give birth and accepts the dragon egg entrusted to her in the dragon's final moments. When the young dragon, Bai Yu, hatches, she recognizes Cui Lan as her mother, and the two begin a life together, relying on each other. Facing pursuit by monks, a siege by villagers, and heavenly tribulations, Cui Lan fights desperately to protect her daughter, while Bai Yu risks her life to save others. After overcoming the tribulations and becoming an adult, Bai Yu accompanies her mother throughout her life. In the end, she transforms into a tree to guard her mother's grave, repaying the kindness of being raised with white flowers blooming year after year.