Curse of Blood and Fortune by Kris Ruhler

To save their loved ones, they must find a cure for calaris. Driven into a corner, Andi and Caden journey to Lintue, where the world’s most talented alchemists reside. But after crash-landing into the city, they’re forced into a shady deal deal with a powerful woman—Adrienne Flint.
Her orders? Locate the only alchemist with a cure.
The arrangement is perfect…until they actually find him. Not only is he a hopeless drunk with a temper, but the ingredients he needs are locked in the impenetrable Yao Apothecary. Breaking in won’t be easy. To make matters worse, an assassin is after the alchemist. With disease spreading among soldiers in the western continent, the cure can tip the balance of Nox’s war. His victory means the end for Eris, Killian, and Aria. Forever.
In a race against the enemy, only two questions remain. Will Andi and Caden find the cure in time? And at what cost?