So between chapter 5 and chapter 20, not a lot of things happened. Tacy met another player named Na-Hyeon. Na Hyeon is with the prince, they were on a expedition to kill monsters. They all talked together and decided to steal a gem or whatever called "Brèche parallèle" in french so the Parallel Breach in english I guess. Lucky as they are, Duke Lloyd planed to give that very stone as a donation for the banquet to celebrate the return of the prince. So the plan is to steal it on the day of the banquet. It's more complicated than excepted, someone knows that they are using magic and there are a lot of guards in front of the room so they can't steal the stone. The guy that interfered with their plan is the little dude from the temple (Pontife Kairos in the french translation). After that, they still stayed at the banquet but another guy came, looking like the prince and trying to frame the real prince to be a fake. Lacy and Ashton helped the prince and the fake one is mad that his plan didn't succeed. With his henchmen, he tried to attack everyone but again, Lacy and Ashton helped and because of Lacy's magic, everyone (but Ashton, the prince, the fake and Na-hyeon) fell asleep. Then, the fake ran away with a magic stone, he teleported himself. Btw I'm not sure but the fake may be called Baron Blaze. Who is Duke Lloyd and Baron Blaze? No idea. What wanted the fake prince? No idea as well.
I tried to explain the best that I can but english is not my first language, I hope you can still understand
Spoilers????