A forgotten ancient power that has been hidden for centuries has began to shake the world. Soul binders, people capable of turning a monsters power into their own, have started to arise and soon what the world thought to be myths are going to reveal themselves to be more real than they could possibly imagine. A veteran hunter Ryo Shoku has been tasked with protecting and escorting a young girl who can supposedly save the world, Astra Safira, from unknown enemies and with minimal knowledge. As they travel across the world he soon discovers that there might be more to this girl than he'd been told.