When Meredith Mitchell's old friend Toby Smythe turns up on leave, she is delighted to see him. But Toby has a problem - or rather his relative Alison Jenner has - and he wants to enlist the help of Meredith's fiance, Detective Superintendent Alan Markby. Alison has been receiving anonymous hate mail which alludes to the murder of her aunt, Freda Kemp, of which Alison was acquitted when she was just twenty. Who is the writer, and how does he or she know about this secret in Alison's past? Markby is at first reluctant to become involved, especially as he and Meredith are busy planning their wedding, but enquiries into a poison pen campaign soon turn into a murder hunt. With the help of Inspector Jessica Campbell, a new member of Markby's team, the investigation unravels a twenty-five-year-old mystery and its dreadful legacy of violence.