In a world of classes and a man made sun, the country's citizens find themselves isolated by moats and terrible insect monsters known as the Gaichuu. Their connections with one another? Letters, written from their Heart, delivered by the brave ones known as the Letter Bees, who are responsible for delivering people's hearts. We start with one such Bee aiming for the top who finds himself standing before his latest letter...which happens to be in the shape of a boy. On their journey together to a town on the edge of their world, they get to learn more about the hearts inside one another, and the young boy learns of the power of the Spirit Amber and the terror of the heart-stealing Gaichuu.
It is following this journey that the young boy decides his future destiny, to be a Letter Bee.
It's a story of people's Hearts, a story of a man-made sun, a story of the strength of a bond, a story of a corrupt government.
This is the story of the Letter Bees.
The Tegami Bachi.