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?

Kate Kinsella is working as a part-time general nurse at Longborough Hospital. The Saturday night shift can be full of surprises, but she wasn't expecting to find her next PI client among her patients. Vanessa Wootten, a fellow nurse, has taken a deadly cocktail of pills in an attempt to take her own life. As Vanessa recovers, she confides in Kate. She's convinced she has a deadly admirer — and she needs Kate's help. Kate is warned to stay away from Vanessa. She has a reputation for being neurotic.