The bone palace - Amanda Downum

Death is no stranger in the city of Erisn, but some deaths attract more attention than others.

When a prostitute dies carrying a royal signet, Isyllt Iskaldur, necromancer and agent of the Crown, is called to investigate. Her search leads to desecrated tombs below the palace, and the lightless vaults of the vampiric vrykoloi. But worse things than vampires are plotting in Erisn - a long-dead sorceress is making a bid not only for renewed life but for the throne as well, and Isyllt's former lover is caught in her schemes.

As a sorcerous plague sweeps the city, Isyllt must decide who she's prepared to betray - the man she still loves, or the royal family she's sworn to defend.