The Castle Behind Thorns

A young blacksmith must piece together a ruined castle—and its mysterious past—in this "graceful and enchanting fantasy" (Rae Carson, author of the Girl of Fire and Thorns series).
When Sand wakes up alone in a long-abandoned castle, he has no idea how he got there. Everything inside is torn in half or slashed to bits—and beyond the walls, a vicious, thorny bramble prevents Sand from leaving. In order to survive, the blacksmith's apprentice does what he knows best—he fires up the castle's forge to mend what he needs. But the things he fixes work somehow better than they ought to. Is there magic in the mending? Or have the saints who once guarded this place returned?
When Sand finds the castle's lost heir, Perrotte, they begin to untwine the dark secrets that caused the destruction. Putting together the pieces—of stone and iron, and of a broken life—is harder than Sand ever imagined, but it's the only way to regain their freedom.