The Ancient Magus' Bride: Those Awaiting a Star.

A three-part OVA series that will tell a story that takes place before Chise meets Magus. Angelica sends Chise some magical supplies, including a gift. The gift turns out to be a book that Chise read in her childhood. Elias asks Chise to tell him the story behind the book. Chise tells him about Miura-san and the mysterious library she found in the forest when she was a child.