Blood on her tongue
(Book)

"The Netherlands, 1887. Lucy's twin sister, Sarah, is unwell. She refuses to eat, mumbles nonsensically, and is increasingly obsessed with a centuriesold corpse recently discovered on her husband's grand estate. The doctor has diagnosed her with temporary insanity caused by a fever of the brain. To protect her twin from a terrible fate in a lunatic asylum, Lucy must unravel the mystery surrounding her sister's condition, but it's clear her twin is hiding something. Then again, Lucy is harboring secrets of her own too. Then, the worst happens. Sarah's behavior takes a turn for the strange. She becomes angry...and hungry. Lucy soon comes to suspect that something is trying to possess her beloved sister. Or is it madness? As Sarah changes before her very eyes, Lucy must reckon with the dark, monstrous truth or risk losing her forever"-- Provided by publisher.