A girl traded her future to save her family's name, then watched her brother burn himself alive clutching a cursed book. The men who find her are not heroes offering rescue, they're handlers in a government library hunting supernatural objects, and they want her to help them find what killed him. She has to solve his death while learning to want someone she was only supposed to marry.

In Imperial Tokyo, the Taisho era has run on for a quarter century past its natural end. Kuze Tsugumi, a daughter of aristocrats, agrees to marry a man whose name she does not even know in order to rescue her declining family. Shortly before the wedding, her younger brother Hitaki mysteriously takes his own life by fire and is found holding an old book. A bureau called Fukurou then appears and tells her about Maremono, books that exert a powerful influence over their readers. Since the incident, Tsugumi can see auras, glowing lights that carry the emotions dwelling inside these books. Despite her unease, she steps out of her sheltered life and into the darkness spreading through the capital, in a supernatural romance.