An "out-of-control spell accident" occurred in the Tiangongfang laboratory. A steam engine automatically carved out an ancient inscription and then destroyed itself. The inscription pointed to the "Key of the Wheel of Time - Child" that had been missing for many years. Lin Yan and Su Jiu were forced to cooperate in the investigation and found that the artifact was hidden in the cargo hold of an overseas merchant ship. The ship had mysteriously sunk at the edge of the Ruins Sea three years ago.
