A pair of researchers remain on their dying planet of Eltria with their two daughters, Amitie and Kirie, in hopes of finding a way to revive the planet, but it was no use. Against her older sister's wishes, Kirie sets off with her childhood friend Iris to seek help from a distant alternate world. They arrive in Japan on Earth to search for the key to their planet's regeneration.
(Source: Anime News Network)
— Description from AniList community (anilist.co).
