Jackaroo: A Novel of the Kingdom (Paperback) by Cynthia Voigt

"False, they were all of them false, the stories; as false as the stories of fairies dancing in moonlight glades on Midsummer Night."
But they served a purpose. In a distant time and far-off kingdom, life is hard. People don't have enough to eat, and winter is upon them. There's little that offers hope, and many turn to the legends of Jackaroo -- the masked outlaw hero who rides at night giving aid to the helpless and coin to the destitute -- for solace. But Gwyn, the Innkeeper's daughter -- sensitive, industrious, and independent -- is too practical to believe such tales.
But when a snowstorm forces her and a young Lordling to seek refuge in an abandoned house, Gwyn wonders if perhaps she has been too cynical. Hidden away in an old forgotten cupboard, Gwyn discovers a package -- a cloak, a mask, a sword....Jackaroo? Could the stories be true?
It takes a shock and a devastating betrayal for Gwyn to begin to understand what -- and who -- Jackaroo really is. And she comes to know what part she will play in discovering the truth, such as it may be, behind the legends.