To repay an enormous debt and save his seriously ill father, Lin Xiao Hai, a young man from Reef Rock Island, is forced to sail a battered boat into treacherous waters. He must battle not only dangerous ocean currents and mysterious underwater secrets, but also the relentless schemes and intimidation of Zhao Heihu, the tyrant who controls the wharf. Relying on his exceptional ability to read the tides and his unyielding determination, Lin Xiao Hai joins forces with his companions to survive the raging seas and the treachery of human nature, fighting against the odds to carve out a way forward.