To kill time, Tetsuya Asahi borrows a forgotten book from his local library. A simple, ordinary novel

— or so he thought.
After slipping a strange bookmark between its yellowed pages, he returns home to find a girl of otherworldly beauty sitting on his bed.

Her name is Erisvelle. Cold. Unfathomable. And completely uninvited.
Against all logic, Soma takes her in. Day after day, the distance between them quietly fades

— through summer fireworks, sunflower fields, and whispered promises beneath an endless sky.

But some books should never have been opened.

Because every page turned alters the world around him. Memories shift. Reality rewrites itself. And somewhere beyond the pages, an unseen presence watches his every move.
Someone is reading his story.
Someone already knows the ending..