Xia Ruya and Xiao Jingnan probably wouldn't have known why such a blunder happened even though their plan was clearly devised seamlessly. They would never know why the truth behind Wen Xinya's death was recorded and played during their wedding.
Actually, it was a simple logic that they had all forgotten: "If you don't wish for others to find out, don't do it in the first place."
The servant of the Wen Family, Mother Wang, was the reason for it all.
