Wintersmith by Terry Pratchett

This book is a sequel to the wonderful 'Hat Full of Sky'. Once again we join Tiffany Aching and the ever amusing Wee Free Men in another whacky adventure. This time though, the spirit of winter seems to have fallen in love with a disinterested Tiffany and much to her horror, he doesn't seem to take any of her hints. If she doesn't figure out how to deal with him, spring may never return.