Luna-tan: 1-mannen no Himitsu
Japanese title: ルナたん～1万年のひみつ～
Type: ONA
Source: Game
Episodes: 10
Status: Finished Airing
Aired: Jun 5, 2017 to Jul 29, 2017
Duration: 3 min per ep
Rating: G - All Ages
Studios: Signal.MD
Producers: NTT Plala, Anime Beans
Genres: Fantasy

There was a land that kept the prosperity of the world using the energy Mana of the titans called Luna. However, when a tsunami struck the world, the land was destroyed. The story takes place ten thousand years after the huge tsunami in the underground. Mokugyo and Toriiruka are the main characters, who are strange animals. "Why are we here?" "I thought we were in somewhere peaceful..." What exactly happened ten thousand years ago? Can Mokugyou and Toriiruka safely return to the surface?

(Source: MAL News)