The powerful, legendary Songmage known as Lullaby managed to single-handedly bring peace to her island. Estranged from her hometown due to her powers, she must learn to live as Ui, an ordinary girl in an almost foreign world that doesn't seem to need Lullaby anymore.

The Island of Aneuf is recovering from a recent, painful war. The city of Aure, to the west, has been the home of the Udari for many generations. The Uman Kingdom, eager to expand its borders, settled the eastern part of the island, and took over most of it until they were stopped.

While the Udari possess superior physical strength and Songmagic, Umans have their own magic and technology. Since they still live close together, and the war wasn't long ago, peace seems far too fragile.

Ui, an Udari, must secretly live among the Umans, and wishes to preserve the peace she created in any way she can. She navigates both societies as she discovers the costs of war, and peace.