After reaching the Dragon Palace of the North Sea, Sun Wukong realized that the North Sea Dragon Prince was not the heartbreaker he was made out to be.
Ao Xuening had always treated his childhood friend, the Green Flood Dragon, as a sister—it was a one-sided love on her part.
Later, Ao Xuening married the second princess of the Eastern Sea Dragon, which led to the Green Flood Dragon leaving in a huff to make her way in the demon realm, where she eventually gained a great reputation and became the renowned Flood Dragon Demon King.
Despite this, Sun Wukong and the Demon King still dragged Ao Xuening out of the Dragon Palace of the North Sea and gave him a good thrashing.
This spectacle made the North Sea Dragon King, Ao Shun, and the East Sea Dragon King, who were taking refuge there, tremble in fear.
Eventually, Sun Wukong and others explained their purpose, and Ao Xuening, knowing he had a guilty conscience, agreed to investigate the northern darklands.