Lang Huan realizes that she can't cure Fang Zhu until the baixi between him and the Emperor is removed, so they go through the process to terminate that night. Lang Huan also tells Fang Zhu in secret that since he is of the special Fang bloodline, if her blood does not match his type, the poison in his body could instead accelerate his death. Regardless, he chooses to go through with it. The Emperor tasks Hai Shi to bring Lang Huan back to the sea. (Source: frankly at MyDramaList)