The Darkening

Vesper Vale is the daughter of revolutionaries. Failed revolutionaries. When her mother was caught by the queen's soldiers, they gave her a choice: death by the hangman's axe, or death by the Storm that surrounds the city and curses anyone it touches. She chose the Storm. And when the queen's soldiers--led by a paranoid prince--catch up to Vesper's father after twelve years on the run, Vesper will do whatever it takes to save him from sharing that fate.
Even arm herself with her father's book of dangerous experimental magic.
Even infiltrate the prince's elite squad of soldier-sorcerers.
Even cheat her way into his cold heart.
But when Vesper learns that there's more to the story of her mother's death, she'll have to make a choice if she wants to save her city: trust the devious prince with her family's secrets, or follow her mother's footsteps into the Storm.