Twins in Japan, the boy born before midnight and the girl after. The girl is promised to a kami associated with her family, and knives can't touch her; the boy appears to have mysterious associations of his own. They become entangled with a mysterious world beyond their ken.
I have no idea whether Carey's version of Japanese folklore is authentic, but it is convincing and fun and slightly horrific. The series is taking a while to get up to speed, though, possibly hampered by its focus on the cautious boy twin, Kai, who seems beyond his depth; impetuous Toshi is strangely a supporting character rather than the protagonist. Also, the obigatory Yakuza element makes me roll my eyes.
Mixed feelings about how color is used in the book, and I have the uneasy feeling the twins' family's features are getting less Asian as the series goes on.