Koyuki, sixteen, is married off to a masked man more than twenty years her senior for the good of both families, and she has never even seen his face. Her husband, Shin, works with spirits, fairies and dragons that most people cannot perceive, and keeps a half-mask on so the things he attracts cannot possess him. At her father's request he loves her only platonically until she comes of age, and the two of them, equally inexperienced, fumble their way toward being a married couple.