Sixth grader Gracie Beck is a talented musician, but after her dad dies all seems lost for her and her mom.
Then Gracie receives a magical songbook with only one song in it, and many blank pages, along with a key on a cord she can wear as a necklace. Wearing the key over her heart, she plays the song from her book and is transported to Uwd. There she encounters the good king of the land, who charges her with carrying his music to the farthest reaches of his kingdom. As a companion he gives her an Uwdian horse with miraculous awareness, stamina, and power.
Through the King’s music, his followers rally around her, but when the enemy army confronts them they’re outnumbered a hundred to one. Facing overwhelming defeat, Gracie must decide if the King’s music alone could ever be enough.