Seventeen-year-old Rose has grown up with her beloved grandmother's stories of mysterious places and mythical beings. More than anything, she wants to live where magic is real. But her mother disapproves, insisting that Rose focus on the dreary practicalities of everyday life.It all changes the night a fey carries her through the Slit into another world. Everything she's longed for is here: an enchanted realm full of wondrous creatures, where magic is the norm and mundanity is impossible.But just as in her childhood stories, the cost is high. Life among the fey means never seeing her human family again. The consequences of failure are steep. And even if she succeeds, Rose's heart is still human ... and some promises are more important than magic.