My Name is not Midnight

Esmerelda Midnight.
Not her true name, but the one she must bear. She is 12, shy, overweight, ungainly. Her destiny is to be a servant to the wealthy Snows and Midwinters, the chief worshippers of Our Lady of the Snows, whose sacred mountain overlooks the bay.
Her teacher, the cruel Sestren Agrippa, is her bane, and also the mistress of the orphanage where Esme lives--the crumbling, mouldering manor where Bloody Bones lives in the cellar, eating bad kids. It seems life will never get better.....