The Tony Hill and Carol Jordan series, written by Val McDermid, follows the complex relationship between a psychologist specializing in criminal behavior, Tony Hill, and a determined police detective, Carol Jordan. The first four books introduce readers to their dynamic partnership as they tackle heinous crimes involving intricate psychological patterns. Their contrasting personalities create tension and intrigue, both in their professional collaboration and their personal interactions.
The series begins with "The Mermaids Singing," where they investigate a serial killer targeting young men. As they delve into the mind of the murderer, Hill's unique insights help the police grasp the killer's motivations. Each subsequent book escalates the stakes, with horrifying cases that challenge their abilities and put their lives at risk.