Right owner of this plaque

"Why did the Crown Prince ask me to see her?" Court Lady Donggu asked. She looked around making sure no one would see them. 

"No one is around. You don't have to worry," Xianwu asserted. 

"Why did His Royal Highness call me here?" Court Lady Donggu asked. The fear on her face showed how terrified she was. 

Xianwu told her not to be scared. "I want Lady Donggu to do a work for me," he said. "Bring me the royal seal that the Grand Empress Dowager uses," he demanded. 

"His Royal Highness knows that I cannot do this," Court Lady Donggu politely refused. 

Xianwu smiled and then laughed at her statement. "Why does Lady Donggu want me to threaten her every time she refuses me? This time I think I need to show her the practical. Shall I bring your son-in-law's head first or your daughter's?" he asked as a grim expression appeared on his face. The only way he could fail the Grand Empress Dowager's plan was if he would receive her royal seal.