When DC Fiona Griffiths says 'yes' to her policeman boyfriend, it's an affirmation that she wants finally to put her psychological breakdown behind her. But she still can't resist the challenge of an undercover policing course, and finding it remarkably easy to assume a new identity, she comes top of the class. So when an ingenious payroll fraud starts to look like the tip of a huge criminal iceberg, she is selected to infiltrate the fraudsters' operation....

Investigating the discovery of human remains that have been frozen for a decade, DI Fiona Griffiths learns that the victim was a missing student with possible connections to Griffiths' father, a case that is further complicated by a recent murder.

"A marine engineer is found hanged in a locked apartment. Some artwork is stolen, then mysteriously returned. A security guard is found dead at the base of a Welsh cliff. When Fiona Griffiths is tasked to look through a stackload of cold cases, her bosses don't expect her to find anything of interest. But then she finds that an impossible robbery really happened. That a nailed-on suicide was anything but. That the dead security guard was almost certainly...