What is the moral of the last joke in Chasing the Witness?

The last cold joke is actually a satire. Xiaoming originally wanted to pursue a horror story, and he paid a huge price. Finally, he found that the most horrible truth was that he had been cheated-for a book that was only worth 15 and the price was 1000 yuan. Extending to the man, he just found a new clue to the car accident nine years ago by chance. He wants to find the female client, hoping to compensate him appropriately and make up for his conscience. As a result, the female client suffered more damage and discovered a series of evil truths. And these are not his original intentions. Like Xiao Ming, he regrets buying that book and seeing so many cruel filth. Unfortunately, the big mistake has been made and no one can undo it.