The story of Xiao, a young diver in The Underwater Universe, who embarks on a perilous quest to retrieve a rare pearl from the depths of the ocean, only to face the might of a sea dragon and the treacherous currents of the Abyss....

When a sea dragon, a symbol of the ocean's power, finds itself in a dilemma, it triggers a chain of events that awaken the ocean's lost dream, leading to a monumental environmental awakening....