Based on Ekaterina Kurae's chapter 16 from the manga, and episode 10.5 of the anime.

Chino Kafuu returns to Rabbit House with a horrified look on her face. When questioned by her friends, she explains to them that she had just agreed to sing the solo section of a song for her class’ graduation ceremony. Although they congratulate their friend on her important role, Chino reveals that she has stage fright, but is determined to overcome it before the ceremony takes place.With the support of her friends and special training from Rize Tedeza, will Chino be able to overcome her stage fright? Gochuumon wa Usagi Desu ka??: Sing for You is a wholesome and heart-warming short story featuring Chino and the other girls from the cafe.

On Halloween night, a young chimney sweep named Lubicchi befriends a man magically conjured out of garbage. Giving him the name Poupelle, Lubicchi is able to recreate a bond he lost when his father died to the tyranny of the Inquisitors—an oppressive force that aims to suppress outside knowledge and the town's true history. But their newfound relationship soon captures a lot of attention, and the threat of the Inquisitors and even the criticism of a few townspeople will test the duo's friendship. In spite of this, Poupelle has struck a particular chord with Lubicchi, and the two conspire to bring the truth to the surface and clear the chimney smoke that clouds the town's skies.