When they were children, Megan adored her younger sister Chloe. Now she can't bear to be in the same room as her. Megan believes Chloe is a psychopath and her sister does appear to be a textbook case: cold, cruel and lacking in empathy. Why does Chloe want to taunt Megan at every opportunity? And why does she persist in manipulating their mentally ill mother, Tilly? When Tilly, under Chloe's malignant influence, becomes dangerously unstable, the consequences are ugly. Megan's world falls apart. Her sister's out of control and there's little she can do about it. Until Chloe's actions threaten the safety of Megan's former lover. A man from whom she has kept an important secret... A study of sibling rivalry and dysfunctional relationships, Sister, Psychopath tells the story of one woman's struggle to survive the damage inflicted by her own flesh and blood.