The box was indeed empty, with no hidden compartments or secret panels.
Meng Qianqian's first reaction was that the contents inside had been taken, but it definitely wasn't Xiao Li. Xiao Li didn't understand Sanskrit; even if she had accidentally opened it by an improbable stroke of luck, she wouldn't have hidden this fact before her death.
If it was taken by someone, then what was their purpose? Why not take the entire box along?
What meaning does leaving an empty box behind have?
To confuse Lin Wan'er? To frame Lin Wan'er?
Lu Yuan mused, "One possibility is that someone got to it first, and the other is that it was originally empty. I lean toward the latter."
After all, even the real Lin Wan'er was merely the daughter of Shen Hou, not Shen Hou himself. Framing her or confusing her would accomplish nothing.
Meng Qianqian turned the box over and examined it carefully: "Why would Hai Pig wait for an empty box? What is so special about this box?"