MC had gone crazy due to some poison/gu. She was able to suppress it, but it would become active again if her thought was unstable.
On her wedding day, her wedding dress was sabotaged with some other poison. Then one of the villain revealed himself, and said that he was her half biological brother, XQ.
MC immediately recognised XQ, as in her 2nd life, he was actually her loyal subordinate. She realised that he was the one who leaked out the formula for explosion, causing her to be viewed as mass murderer in her 2nd life.
XQ also revealed that MC's mother was in fact, still alive.
At that point, MC was still able to calm herself, but then XQ threw a severed hand to her. MC recognised that hand, it was the Emperor's, the Emperor who just died the other day, they had stolen his corpse. XQ threatened MC that if she wasn't obedient, he would throw the Emperor's corpse to be eaten by dogs. MC thought of how the Emperor was very sick before he died, yet still thinking about her happiness, so she couldn't endure anymore and became mad.