Ex-Detective Inspector Hillary Greene returns to Thames Valley to work on cold cases for her new boss. Now a civilian, she not only has to cope with the loss of her professional status, but she has also acquired a stalker. When her superior, Superintendent Steven Crayle, is unsure about letting someone with Greene's reputation on his team he hands her a 20-year old murder file that's as cold as a blizzard. Who would want to slaughter a housewife and loving mother of three in her own home? And after all these years, if the original team couldn't make a case, what chance is there of justice now? With something to prove, to both herself and her new boss, Hillary Greene knuckles down to catch a killer.