Joy of Life opened the box in episode 28.

Qing Yuannian opened the box in episode 28.
In Joy of Life, the box was opened on episode 28.
Joy of Life opened the box in episode 28. Fan Xian had gone through many twists and turns to steal the key in the Royal Palace and work with Wu Zhu to open the chest. The chest contained a hot weapon and two letters Ye Qingmei had left for Wu Zhu and Fan Xian.
Joy of Life's box contained three parts of a Barrett sniper rifle. It was a letter for Wu Zhu and Fan Xian. The chest was divided into three layers. The first layer contained the parts of the Barrett sniper rifle. The second layer contained a letter to Wu Zhu, expressing his longing for Wu Zhu and his wish for him to destroy the chest. The third layer was a letter to Fan Xian.
The box left behind by Ye Qingmei in Joy of Life contained three layers of items. The first level was a Barrett sniper rifle. It was a peerless weapon used to deal with the Qing Emperor. The second layer was a letter to Wu Zhu, expressing Ye Qingmei's longing for Wu Zhu and her wish for him to destroy the chest. The third layer was a letter to Fan Xian, mentioning Fan Xian's background and Ye Qingmei's origins. Fan Xian's background was very special. He was not a transmigrator, but a test subject, the only successful test subject in an experiment to turn memories into data. Fan Xian needed to open this chest to understand more of the truth. Thus, the box contained the Barrett sniper rifle, a letter for Wu Zhu, and a letter for Fan Xian.
In Joy of Life, Ye Qingmei had left Fan Xian with a Barrett sniper rifle and two letters. This sniper rifle was a top-notch weapon from Ye Qingmei's previous world. It had the strength of a martial grandmaster. The two letters Fan Xian's mother had left behind were addressed to Wu Zhu and Fan Xian respectively, revealing Ye Qingmei's feelings for them and some secrets about this world. Apart from that, the box had three more layers, but the specific contents of the other layers were not mentioned.
In the TV series Joy of Life, the opening of the box was in episode 28. Fan Xian successfully broke into the empress dowager's bedroom and stole the key. By inserting the key and entering the password, he could open the chest with three layers of contents. The box contained a Barrett sniper rifle and two letters Ye Qingmei had left for Wu Zhu and Fan Xian.
The opening of the box in the TV series celebrating the year was in episode 28.
Joy of Life episode 28 Fan Xian and Wu Zhu opened a mysterious chest together. Fan Xian's mother had left behind this box. Inside was a sniper rifle and a letter to Wu Zhu. In the letter, it was revealed that Ye Qingmei was not a person of this era, and Wu Zhu was a robot. Fan Xian and Wu Zhu found the key to the chest and successfully opened it. However, the specific process of opening the box had been edited in the movie, so some details were not shown. Therefore, the specific details of the box opening could not be found from the search results provided.
The box in Joy of Life was opened in episode 28. Fan Xian and Wu Zhu worked together and used the key to open the chest. The box contained three parts of a Barrett sniper rifle and two letters Ye Qingmei had left for Wu Zhu and Fan Xian. This sniper rifle was brought out from the temple by Ye Qingmei before she transmigrated. It had powerful lethality and could rival a martial grandmaster. Fan Xian unlocked the box with voice and found something unexpected. Therefore, the box in Joy of Life was opened in episode 28.