The film is based on selected chapters of Wu Cheng'en's classical novel ''Journey to the West'', and tells the story of how Sun Wukong rebels against the Jade Emperor of Heaven.
500 years after Sun Wukong's (Aaron Kwok) imprisonment under the Five Fingers Mountain, a young Buddhist monk Tang Sanzang (Feng Shaofeng) sets out for a journey to the Thunder Monastery in India to collect Buddha's scriptures. When he is attacked by a tiger, he is forced to free Wukong and the Monkey King learns that he has to protect the monk throughout the journey, because the Bodhisattva Guanyin ensured he would be bound by an enchanted circlet that can cause him pain whenever Tang Sanzang chants a certain sutra. Soon the duo meet Zhu Bajie (Xiaoshenyang), a lustful pig demon, and Sha Wujing (Him Law), a djinn-like monk. He fights a dragon, defeats it and transforms it into a horse as his mount.
In The Monkey King 3, Buddhist monk Tang Sanzang (William Feng Shaofeng) and his disciples – Wukong the Monkey King (Aaron Kwok Fu-shing), pig demon Bajie (Xiao Shenyang) and the blue-skinned sand demon Wujing (Him Lo Chung-him) – inadvertently enter the Womanland of Western Liang, a nation populated by women raised to believe that men are fatally deceptive in matters of the heart.