After Traveling Through Time, I Found Out That My Best Friend Was in a Sadistic Novel. How to Solve the Problem?

Reincarnated in the world of Xianxia, ​​he lived for seventeen years only to find that his best friend was trapped in a bloody sadomasochism novel, and the plot of this book also took place in this world. Seeing that this unlucky child was about to meet the hero Shen Jingbing, he hurried to the capital to fish for him, but... Was this the capital in the book? Why are the concubines in the harem holding a concert tour, why are the four sets of imperial examination prediction papers flying all over the place, why is it that while shopping, there is a street specializing in "selling one's body to bury one's father", and the No. 7 Contestant who buries one's father, isn't she the senior sister she went down to train with last year?