The Broken Sword: Halcyon (Volume 2)

Master swordsman Lorenzo Quesada believes he can peacefully restore his country's prosperity and honor using the legendary Skyfire Stone. But Salvator Fabris, the most feared fencer and assassin in Italy, also wants this holy relic.
 
And then famed inventor Taziri Ohana arrives on Lorenzo's doorstep with a tale of a horrible plane crash and three frightened passengers: a scholar, a politician, and a scowling Italian chemist named Dante. Unwilling to abandon strangers in need, Lorenzo takes them with him across the wintry wastes into the mountains, where they encounter creatures far more terrifying than mere assassins.
 
But when the holy relic is stolen, Lorenzo and Taziri must prevent a war that could destroy all the nations of the Middle Sea, even if it costs them both their lives.
 
The Halcyon trilogy of steampunk thrillers:
Book 1: The Burning Sky
Book 2: The Broken Sword
Book 3: The Bound Soul