In Arboral Year 1294, the world is dominated by nine massive towers known as the Spires--remnants of an advanced civilization, they are filled with lost secrets and powerful knowledge that nations struggle to possess. Luca is a bugler in a mercenary company who wants nothing more than to leave the battlefield behind and become a true musician, a maestro. But marked as one of the enigmatic Branch-hexed, and gifted with the strange ability to see the sound of his instrument, Luca finds himself drawn reluctantly into a war of epic proportions!

Left for dead after a battle, Luca is saved by the mysterious Pontiff and learns he is not the only person with unusual powers. The Pontiff has formed a special team of Branch-hexed individuals he plans to use to help him defeat rival empires--and Luca learns that his powers, rather than being an escape from the battlefield, now force him to be a muse of massacre.