The Assassin's Curse - Lindsay Buroker

The Assassin's Curse is a short story that meshes with the Emperor's Edge series. I suggest reading The Emperor's Edge first. The order with respect to the rest of the series isn't crucial.

Amaranthe and Sicarius find a destroyed Turgonian military steam tramper containing a cache of new weapons prototypes. They suspect Nurian spies of trying to steal the technology, but the spies flee to Darkcrest Isle. Darkcrest Isle is cursed by the spirit of a Nurian warrior mage. Amaranthe and Sicarius have to stop the spies without falling under the curse. It won't be easy. A great short story in the Emperor's Edge timeline. Very highly recommended.