The Flower and the Flame by Talia Devereaux

No, Odette could never belong in Ocovielle. She belonged to another world entirely, to the Lands of Everlasting Change, where it was said that the earth was as conscious as its fauna, the rivers flowed with milk, trees oozed with honey, and the fair folk celebrated with revels night after night. She wanted to see it more than anything in the world.
One day soon, she’d make her way there, to the realm of Faery. She’d fight tooth and nail through her stepfather’s chevaliers de fer, no matter how harsh the battle. The iron-armoured guards would fall easily beneath her blade, vanquished in her fervour. She’d bear past the cursed iron gates and finally, finally, escape. Doubtless, her stepfather would send a hundred men after her, but what of it? When that day came, Odette would be ready.

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When Odette’s brother is whisked away to the Lands of Everlasting Change by a faerie, she must escape from her stepfather’s iron prison and find her way there to rescue him. Along the way, she enlists the help of a speedster thief, a trickster faerie and a blue pixie. Together, they journey through treacherous human-infested lands, discovering life-altering secrets of their pasts.