It was finally discovered that Cui Zhu was responsible. Cui Zhu, lazy and negligent, had been caught several times by her personal Sister Su, who then reported her. She scolded Cui Zhu and fined her monthly money, clearly stating that if she didn't improve, she would be sold and sent away from the mansion.
Instead of repenting, Cui Zhu harbored resentment against her. Taking advantage of nap time, she drugged the young Ling Yao with medicine, rendering her unconscious, and threw her into the pond. Had Sister Mu not felt that something was amiss and gone out to search for her, Ling Yao would no longer be alive.
Attempting to murder one's master was a capital offense. She executed Cui Zhu in front of all the servants in the house as a warning to others.
Unexpectedly, Ling Yao witnessed it and thus came to believe that she was a heartless monster. How could she bear such a burden?
Cradling his shaky wife gently, Nangong Yelin was filled with self-reproach and regret.