Okay,guys! I know some of you are confused because of the title and the days that the story was finished. So, let me explain the main plot of this book.

If you'll gonna read the book 1, the TWICE version, you will read that the main purpose is to bring back the normal body or the real members back to the real world. Why? 

Because, the antidote was missing. There's no antidote! The victim will gonna be a baby for 30 days but, the other members or his/her family needs to find the antidote in that 30 days.

That means, the story can be finished in exact 30 days or earlier than the expected, as long as the antidote was made and the suspect was caught.

Why was the antidote in the Book 2 was different to Book 1?

It is because, Tyro made Nako, Minju, Hitomi, and Yuri drink a more powerful baby potion that have a stronger and different substance in it while the baby potion that Professor Han made Tzuyu, Chaeyoung, and Dahyun drink was the normal one (because they are the first target so it was obvious).

These are the questions that I think you want to be answered but I hope I answer it very well. 

Bye!