The 13th of May is famously the unluckiest day of the year. Sergeant Caleb Martin of Kingsmarkham CID had no idea just how terminally unlucky it would prove, as he embarked upon his last day on earth …

Ten months later, Wexford is confronted with a murder scene of horrific brutality. At first the bloodbath at Tancred House looks like the desperate work of a burglar panicked into murder. The sole survivor of the massacre, 17-year-old Daisy Flory, remembers the events imperfectly, and her confused account of the fatal night seems to confirm this theory. But more and more, Chief Inspector Wexford is convinced that the crime lies closer to home, and that it has sinister links to the murder of Sergeant Martin …