A Hei, the black dog raised by Yang Shanyu, the youngest son of the Yang family, sees his master die after crashing into a tree. The sight wakes the old Lord Lao sleeping in its branches, inspiring him with an absurd idea... From then on, A Hei sets out on the path of cultivation... After countless twists and turns, escapes, and acts of mercy, he is finally accepted as a disciple by the Supreme Lord Lao and gains immense power. He leaves the mortal world behind and begins slaying demons and vanquishing evil. His extraordinary intelligence catches the eye of the Primordial Creator, who entrusts him with the Ancient Immortal-Sealing Pagoda. This sparks the displeasure of the immortals in Heaven, but the Primordial Creator believes in A Hei (Dog Sanjie, the Thunderclap Hound, the Canine God, later renamed Yuanzun) and sets him a series of challenges, which Dog Sanjie overcomes one by one.
