Wan Donglin didn't hide it from her: "Have I not been looking for that lost item all this time? Before my father passed away, he never actually told us its specifics, not even my mother, who only had suspicions. Otherwise, it wouldn't have been left here for so long. It wasn't until the theft that we realized something was seriously wrong..."
Because it was important, and since Old Man Wan deliberately concealed it, he only hinted to his wife about it before he died. Liu Daqing didn't pay much attention initially, but after this major incident, she recalled past experiences and made some deductions.
Therefore, Wan Donglin's search was a complete mess, with no clue where to start.
"Old Zhou and that person..."
That person is Old Zhang.
