Kate Kinsella is in her office above Humberstones Funeral Directors, contemplating her first real murder case as a private investigator. Jacky Byfield, a nurse at rundown St. Dymphna's Hospital, was stabbed to death on the grounds while running an errand on her night shift. The police have hit a dead end. Jacky's family are desperate for justice, and it's up to Kate to get results — and catch a killer. Kate decides to go undercover at St. Dymphna's. But three more people die in suspicious circumstances while she's there — including her prime suspect. Will Kate become the fifth victim?