Ar Tonelico

Ar tonelico (アルトネリコ, arutoneriko) is a multimedia project series made in collaboration by Gust Corporation and Banpresto (currently subsidiaries of Tecmo Koei and Namco Bandai Games respectively) consisting of video games, manga, and an OVA, until it was succeeded by the Surge Concerto series. The OVA entitled Ar Tonelico: The Girl Who Sings at the End of the World (アルトネリコ 世界の終わりで詩い続ける少女) aired on March 22, 2006 based on the same RPG game name

Plot
A long time ago on the planet Ar Ciel, a great man-made catastrophe caused the planet to lose its land, and the interaction between the protagonist and the heroines through a work of science fantasy tells the story. The heroes ar generally being members of a race called Revatail, which can use a special ability known as Song Magic. During the course of the game trilogy, the people were forced to live on three gigantic structures they made after the land was lost, with loss of communication between the regions, leading the people to believe that the region where they once lived was the entirety of the "world" that existed.

In the OVA. Aurica Nestmile is a young Reyvateil, who feels her song magic is not of much use to anyone. From high up on the tower Ar Tonelico comes Lyner Barsett, whose airship is totaled upon impact with the ground. These two meet up, and in the search for someone who can repair the ship, end up helping both each other and themselves.