Because Yulan is the maid of Zhang Dujian, she accepted Zhang Dujian's order to frame Wu Song. After helping Wu Song pity Jiang Menshen, Jiang Menshen bears a grudge and colludes with Zhang Dujian and the British to frame him. But Wu Song is a very cautious person. In order to gain his trust, Zhang Dujian betrothed his maid Yulan to him, which made him relax his vigilance.

Extended information:

Wu Song didn't accept the marriage at first, and took Yulan as his sister. As they get along with Yulan, their feelings become deeper and deeper, and Wu Song also likes Yulan very much. One day, when Yulan was helping Wu Song with housework, she asked Wu Song if she wanted to buy a box, and put all the money and jewelry that Zhang Dujian sent in the box. Wu Song said she would buy it if she liked it.

Until one day, Wu Song suddenly heard someone shouting "Stop thief" in the hospital. He is a sentient and righteous man, and thinks that Zhang, the supervisor, is so kind to himself that he can't sit idly by. Then he took up arms to catch the thief, but he was cheated.

The lost things have been put in the box bought for Wu Song. Song Wudang asked Yulan if she bought a box for herself. Yulan denied it. Wu Song's heart ached. It turned out that this was a trick they had already arranged, just waiting for themselves to jump in, and Yulan was also an accomplice of Zhang Dujian. On the way to the cell, they arranged a killer to take Wu Song's life. Although Wu Song is very kind to Yulan, Yulan is just a humble servant girl who dare not disobey her master's orders.