Which integrated knife is the old version of Zhu Huan Gege Wei Zi?

Zhu Huan 1 episode 19

Swallow had a big fight with Yongqi about picking lotus, and she accidentally fell off her horse while riding with Yongqi. Yongqi was distressed and showed her mind to Swallow. Swallow couldn't hold back her thoughts, and finally smiled through tears, and made up with Yongqi, and the storm finally subsided. When a group of people passed by the river, they happened to meet a group of squire elders singing poems in pairs. Gan Long ordered Wei Zi to join the poem, and Wei Zi fulfilled her mission as she wished, which made her deeply loved by Gan Long and made her position clever gradually. One day, a group of people were watching in a crowded market. Wei Zi and Gan Long met an old couple selling tea eggs. Suddenly, they pulled out their hidden knives and stabbed Gan Long. At that time, the situation changed. People in the city became assassins and often attacked Gan Long. Wei Zi saw that the situation was urgent and desperately went to find a knife for Gan Long. However, Wei Zi's weak body was greatly hit, and she fainted at once. When Qianlong saw this, he was frightened, and Erkang was even more worried. He quickly grabbed Dr. Hu for treatment. Wei Zi finally narrowly missed this difficulty, but Erkang saw Gan Long's careful care for Wei Zi and the care faintly revealed in his eyes, which made Erkang realize that this matter could not be delayed any longer, so he made up his mind that as soon as Wei Zi recovered, he would take Wei Zi with him and stay away from this flashpoint.