Princess Floralinda and the Forty-Flight Tower — Tamsyn Muir

When the witch built the forty-flight tower, she made very sure to do the whole thing properly. Each flight contains a dreadful monster, ranging from a diamond-scaled dragon to a pack of slavering goblins. Should a prince battle his way to the top, he will be rewarded with a golden sword—and the lovely Princess Floralinda. But no prince has managed to conquer the first flight yet, let alone get to the fortieth. In fact, the supply of fresh princes seems to have quite dried up.And winter is closing in on Floralinda...