If there was a regret medicine in the world and God gave you a second chance to choose, would you make a different choice? What you love, what you care about, everything about you... What are they to you? Human beings are very complex and too fragile. The word love is too heavy for human beings. Do you want to believe in the word love? But in the face of the reality of this world, will you firmly believe in the things you once believed in? Or, you just want to find a reason to go around, even if you become someone else's puppet, it doesn't matter? And as a puppet, are you willing to make a huge gamble with the entire universe as a bargaining chip?
Concept: The protagonist's growth story from youth to maturity when he has just entered that world.