Why did Jiu-Er's daughter Guan Qi die?

In the 59th episode, I was deceived to the county seat by my lover and killed by Japanese soldiers when I escaped.

Lianer told Jiu-Er that she had been abandoned by Yu Zhanao and begged Jiu-Er to take her in, hoping to get back together with Jiu-Er. Jiu-Er was very happy, but I didn't think it would invite the wolf into the room. Lianer tricked Guan Qi and Dou Guan into taking them to see Yu Yan. On the way, Dou watched something wrong and tried to stop Lianer, but Guan Qi was taken away by Lianer. Officer Bean ran back to Jiu-Er and told him about it. Jiu-Er also noticed something was wrong, so he asked the bean officer to find someone to inform Zhan Ao, while he searched for Guan Qi along the way.

Even two brought Guan Qi into the city, and Nomura put them under house arrest to attract them to occupy the Aojiang River. Officer Dou tipped off Zhan Ao that his daughter had been taken away. Whether this was a trap set by the Japanese or not, Zhan Ao insisted on the rescue, but Jie Jun failed.

Yu Lang told Lotus the truth, and Lotus knew that she had been cheated at this time, so she was in big trouble. Jiu-Er found Yueben, who asked her to find Yu Zefu, and Jiu-Er asked Nomura to take her to see Guan Qi. Jiu-Er talked to Lianer alone and slapped her in the face, while Lianer told her that she had been jealous of Jiu-Er for many years and told Jiu-Er about Yueben's plot. Jiu-Er knew that she couldn't remain official, so she went to see her daughter for the last time. The Japanese army shot and killed Lianer and Guan Qi, and Jiu-Er stopped Yu Zhanao on the way, kneeling to stop him from rescuing Guan Qi, and the two embraced and wept.