The Princess makes a joke out of LCL by showing her a black cat. The cat was covered with ash, dirtying her face and clothes.
LCR gets the news that Prince NA went to the palace late at night and was very happy when he came back...
There is a banquet happening at the palace. The Queen gives a robe to Lady Yu at the banquet. After wearing it, Lady Yu faints and dies. The guards search in the Clothing Department to look for the culprit. They found the poison in LWY's clothes.
She is brought to the King. Prince Dong Ping accuses LWY of working with Prince NA since the poison could only be found in the place that Prince NA just came back from. Prince NA tries to deny his relationship with LWY but is interrupted by Prince DP every time. LWY then requests to speak with the King alone.
She states that she is the Northern Liang princess and is at the mercy of the King. She reasoned that she wouldn't need to work with Prince NA to harm the Queen if she was seeking revenge - she would directly try to harm the King. The King questions whether there is something going on between her and Prince NA and whether she would use him in the future. LWY states that she wouldn't be manipulating anyone. The King gives her three days to find the real culprit. If she didn't find the person, she would be guilty of the deed.
Prince GY is waiting outside and asks her what happened and pretends to still hate her when Prince NA arrives. Prince NA feels bad for pulling her into the problem as well. LWY states that he saved her life so it doesn't matter. Prince NA promises to protect her.
Prince GY does his own investigation on the maids at the Clothing Department.