A woman is dead, her throat and midsection viciously slashed open, a lethal dose of heroin found in her system. But what makes this grisly New York outrage different from all the others — and tosses the "red-ball" squarely in Detective Paul Devlin's lap — is the fact that this victim was a nun. Blistering heat is coming down from the mayor's office, One Police Plaza, and the Archdiocese, so Devlin needs to find a murderer, and fast. But suddenly walls are being made to derail an investigation that is leading Paul Devlin and his people in a shocking direction: into the secret, fortified heart of the Catholic Church itself — and toward a terrifying conspiracy cloaked in silence, piety, and blood that extends wider than anyone ever imagined.