Hottarake no shima - Haruka to maho no kagami

Haruka lost her mother at a young age. While her mother was still alive, she received a treasured hand mirror from her. After her mother's death, forgot about the mirror, and eventually lost it. One day, she decides to go to a local shrine and pray for the return of her lost mirror. It is there that she accidentally encounters a small masked creature which she secretly follows to the land of forgotten items. (Wikipedia)