Sugar Apple Fairy Tale, Vol. 7 (light novel) — Miri Mikawa

As Anne gets ready to open a sugar candy workshop of her own, she receives a mysterious request from the royal palace. If she can promise to keep everything she learns a secret, she will be allowed to help a group of first-rate candy crafters complete a job for the queen herself. But why all the secrecy? What mysteries await Anne on her first trip into the castle?