A child killer awaits the outcome of her insanity defense from prison. Outside, a criminal psychologist catches a shocking tell in a news reel: as the killer lowers her head to avoid questions from reporters, a self-satisfied smirk momentarily appears on her lips…

A series of child murders upends life in a southern fishing village in 1980s Taiwan. The female killer sits in prison as her insanity defense plays out, but a death sentence seems inevitable. With time running out, criminal psychologist Wang Yueh-hsueh visits death row to interview the killer and collect a first-hand account for her research.

From the court records, Yueh-hsueh knows the killer used her status as a "friendly neighbor" to ingratiate herself with local children before giving them poisoned candy. The records also show that she looked on, expressionless, as the children were rushed off to the hospital. Yueh-hsueh uncovers further facts about the killer: she became infertile after an illness, and when she was a teenager, her mother forced her to marry a man twenty years her senior. What was the truth, then? Was she a meticulous and calculating serial killer, or a woman who had lost her mind after suffering too much trauma? In their meetings, Yueh-hsueh tries every means of gaining her research subject's trust, all to no avail. Finally, when she mentions her mother, the killer points to an empty corner and says, ""You can see her, too, can't you!"" What unfolds from there will leave Yueh-hsueh questioning her own sanity as much as the killer's.

Based on true events, author Karasumi conducted extensive archival and field research before adapting the notorious case of Taiwan's first female serial killer into a crime/suspense novel, incorporating both details of the investigation and real-life controversies surrounding capital punishment. If not via the death sentence, how can a society discourage the most heinous crimes? If the legal system isn't the solution, how do we address the social problems that lead to criminal behavior? More than just a crime thriller adapted from true events, A Sketch in Scarlet addresses social issues that will keep readers thinking long after the book is returned to the shelf.