The Book of Atelier of the Sorcerer's Hats. Volume 9 by Kamome Shirahama

A parade of shooting stars signals the start of the holiday. Coco and her friends are going to take part in the Silver Night festival fair. They are well prepared and ready to show everyone their creations.
The fair seems to have taken over the entire city: food stalls, decorations, and far too many people eager to celebrate. The city is more alive than ever.

Meanwhile, in the royal castle, where magic is forbidden, a meeting of nobles and wizards is taking place. So everyone will be at the fair: wizards, aristocrats, wise men... and uninvited guests, whose intentions are still unknown to us. A lot of power has gathered here, so anything can happen.