Bride in Red, Bride of Bones

The Yules are the richest family in the country and they recruit daughters-in-law out of remote mountain villages using a single requirement, that the girl be extremely thin. What the requirement is for is a piece of sorcery: the life force of a pregnant woman, drawn off to keep their sickly heir Jude alive. Girl after girl has gone into that house and not come out. One of them was Rose Dane's older sister, sent there by their own father after he starved her down to the required shape, and returned to the family dead. Rose spends three years making herself into what the Yules ask for, keeping herself hungry until she matches the standard, and then marries into the household herself. She sets out to learn exactly how the thing works, and once she has learned it, to turn it back on the people who built it, which also means settling accounts with her father and the greed that made him hand over his first daughter.