DEEMO: MEMORIAL KEYS

A girl who fell from the skies and lost her past Deemo who plays the piano all alone in the world of the treehouse an accidental encounter between the two. The music flows as the fingers hit the piano keys. The start of a fairytale journey has begun... 'Before turning to leave, don't forget to say one last goodbye.' (Source: Anime News Network) — Description from AniList community (anilist.co).