Of course, Chen Pingping did not believe it. As a man from that time, he knew about the chest in the hands of Lady Ye. When she was attacked, she did not use this chest. This meant, at the time, the chest was not in the Taiping Courtyard. After the incident, in Chen Pingping's thorough search of the Courtyard, he still did not find any trace of it.
Naturally, this out-of-the ordinary object could not have casually been lost.
Then, only Wu Zhu knew the location of the chest. With Fan Xian gradually growing up and living in such a dangerous environment as Jingdou, Wu Zhu would certainly have given the chest to Fan Xian to carry around to avoid danger that could come at any time in case he was injured and couldn't be beside him.
This was Chen Pingping's deduction. His deduction was not very far away from the truth.
However, he was wrong on one point. Neither he nor the Emperor had ever personally seen that chest, so they had no idea of its volume and size.
