Silvercloak by L. K. Steven

Two decades ago, the Bloodmoons ruthlessly murdered Saffron's parents, destroying her idyllic childhood. Hellbent on revenge, she lied her way into the elite Silvercloak Academy of detectives with a single goal: find a way to bring the Bloodmoons to justice.

But on the eve of her graduation, her deception is expose, and she's given only one option: go undercover and tear the Bloodmoons down from the inside.

Descending into a world where pleasure and pain are the most powerful currencies, Saff must commit some truly heinous deeds to keep her cover - and her life. Not only are there rival gangs and sinister smuggling rings to contend with, there's also her growing feelings for the kingpin's tortured son, and curious prophecy foretelling his death at Saff's hand.

With each day testing her loyalties further, Saff's web of lies becomes harder to spin. And when one false step could destroy everything and everyone she's ever loved...the mage who dedicated her life to vengeance might just have to die for it.