Ship of Smoke and Steel by Django Wexler

In the lower wards of Kahnzoka, the great port city of the Blessed Empire, eighteen-year-old ward boss Isoka comes to collect when there’s money owing. When her ability to access the Well of Combat is discovered by the Empire—an ability she should have declared and placed at His Imperial Majesty’s service—she’s sent on an impossible mission: steal Soliton, a legendary ghost ship—a ship from which no one has ever returned. If she fails, her sister’s life is forfeit.