The film tells the story of the genius detective Hu Bayi helping his friend Uncle Ming to go to the South China Sea to salvage pearls. While they were on their way there, they unexpectedly met with a shipwreck, sinking into the sea. However, thanks to this, they accidentally found a sunken ancient ruins of a thousand years. A series of obstacles come at them as they explore the seabed, but through cooperation and trust, they manage to get together and escape the various traps set in this ruin.—iQIYI