I've SOLVED it!!! Yes, SOLVED it.The Synopsis is not wrong!I've solved the mystery to why the plot is so different from the synopsis.First of all CHECK the author's name.Yes, the author name is 'younger sister'. That's right, the author is the Mc's younger sister before transmigration.Now for the explanation. The mc wrote the book, died and was transmigrated (as explained in chapter 1). however, his omnipotent devastated 'younger sister' decided to revive to him and heavily modify the contents of his book, claiming the book as her own, before posting it on online platforms, such as (webnovel), which explains the why the summary didn't tally with the first chapter. Don't forget it's his point of view, not the author's.Aside from the characters names and identity, from his previous novel, the plot is completely changed so we can officially consider the edited book as his sister's.To started off, she revived her brother by transmigrating him into the body Lin Yao. Why Lin Yao? Yes, his character settings has a 'younger sister'. Maybe just to remind him of his previous younger sister.Next, she further awarded most of the female leads with the system, with its primary objective to force them to be in a relationship with her brother. Maybe to spite him as he didn't have a girlfriend in his previous life.As for the notebook he received on his birthday? He hasn't found it yet. Now let's hope he doesn't find it, or the fourth wall will be broken. ??Back to the Synopsis last sentence "Sis, where is your future sister-in-law?"Good Question! Younger sister, the Author, aka, GOD, shall award all potential candidates with the system. The winner will be the one who has completed all of the system tasks and marry him as the reward.10/5 if my bulls*** is actually right.Please like this to give the novel more love. Who knows? I might actually be right.