In The Crescent Stone by Matt Mikalatos, Madeline, a teenager with terminal lung disease, meets a mysterious stranger who offers to heal her in exchange for one year of service in his world, the Sunlit Lands. Madeline and her friend Jason travel to the Sunlit Lands to work for the Elenil people. There is much to discover and enjoy as privileged members of the fantastical Elenil society, but Madeline and Jason soon learn that magic must be bought at a high price.
