When Sun Wukong was trapped under Wuzhi Mountain for 400 years, he happened to be rescued by Ah Yi. Ah Yi's parents were killed by the Dragon Prince, and she wanted Sun Wukong to take her to the Heavenly Palace to lodge a complain. The Dragon Prince learned that Sun Wukong had escaped from Wuzhi Mountain, and was going to avenge the destruction of the Dragon Palace in the East China Sea, and used Sun Wukong's good brother, the Demon King, to assassinate him. Although Sun Wukong was blocked by Ru Lai's mana, the Bull-Demon King still failed to assassinate him. But he brought Ah Yi back, and in order to save Ah Yi, Sun Wukong hit the Dragon Palace. Sun Wukong and the Dragon Prince fight from the sea to Nantianmen. Sun Wukong was finally coerced by Ah Yi and returned to Wuzhi Mountain to continue his practice, waiting for someone with a predestined relationship.