Casket of Souls (Nightrunner #6)

The Nightrunners are back in this gripping novel full of Lynn Flewelling's trademark action, intrigue, and richly imagined characters.
More than the dissolute noblemen they appear to be, Alec and Seregil are skillful spies, dedicated to serving queen and country. But when they stumble across evidence of a plot pitting Queen Phoria against Princess Klia, the two Nightrunners will find their loyalties torn as never before. Even at the best of times, the royal court at Rhiminee is a serpents' nest of intrigue, but with the war against Plenimar going badly, treason simmers just below the surface.
And that's not all that poses a threat: A mysterious plague is spreading through the crowded streets of the city, striking young and old alike. Now, as panic mounts and the body count rises, hidden secrets emerge. And as Seregil and Alec are about to learn, conspiracies and plagues have one thing in common: The cure can be as deadly as the disease.