The Princess of the Tower Wants a Hero

Princess Lumi has been held captive in the demon lord's castle situated in a land of everlasting winter. She hates it. It's cold, it's lonely, the food is bad, and there's literally nothing to do! The only good thing about this place is the tea and snacks. Princess: "I know I said I'd help you out, but I am exhausted. I'd be willing to do something else though." Hero(?): "Of course! As long as you don't kick me out of here." These are the days of winter they spent together.