A young boy with a strange demeanor suddenly finds himself dealing with a beautiful green haired girl stuck in his mind. She doesn't remember much of anything, and loves to sleep, however it's clear that there is a deep connection between the two of them.

The son of a mercenary, all he has known is constant travel and bloodshed. Now tied into a greater fate than anyone realizes, how will they survive being thrust onto the world stage full of powerfully gifted nobility, an ever dominant central church, and a mysterious hidden force lurking in the shadows.

Follow Byleth as he grows up in a world of magic and mystery, grappling with powers he doesn't entirely understand and forced to combat those who would seek the mysterious girl for their own purposes.

You do not need knowledge about Fire Emblem to read this. The story can also be dark at points, but that is by no means the focus of the novel.