The Ten Thousand Doors of January by Alix E. Harrow

In a sprawling mansion filled with peculiar treasures, January Scaller is a curiosity herself. As the ward of the wealthy Mr Locke, she feels little different from the artefacts that decorate the halls: carefully maintained, largely ignored and utterly out of place.

But her quiet existence is shattered when she stumbles across a strange book. A book that carries the scent of other worlds and tells a tale of secret doors, of love, adventure and danger. Each page reveals more impossible truths about the world, and January discovers a story increasingly entwined with her own.