Makkuramori no Uta
Japanese title: まっくら森の歌
Type: Music
Episodes: 1
Source: Original
Producers: NHK
Duration: 2 min
Rating: G - All Ages

When the last ray of the sun disappears, the day ends. But in the forest, a world that is hidden during the day awakens with the darkness.

(Source: Anisearch)