No-nonsense detective inspector, Jack Frost, is caring for his terminally ill wife when he is forced to assume command of an investigation into the disappearance of a young girl, Tracy Uphill, aided by DC Clive Barnard, the Chief Constable 's nephew. Her mother, Linda, had been late picking up Tracy because she was working as a prostitute. The police search for Tracy uncovers skeletal remains with a locked security box handcuffed to his severed wrist.
Tracy is eventually dropped off unsconscious at a hospital, but cat fur leads them to a local cat lady, who had abducted Tracy because she was being abusive towards her, but returned her when she fell ill. Garwood is found shot dead by the same gun, leading Frost to the retired bank manager, Gerald Powell. Cornered, Powell explains that he took money from a wealthy customer's account to bail his son out of debt, but the son killed himself when Powell refused to provide even more funds.
When the wealthy customer died, Powell had to urgently replace the money, and plotted with Felton—who was blackmailing him—to stage a robbery during a cash transfer, during which the unwitting Garwood would be knocked out. However, Powell forgot the keys to unlock the safebox, and when Felton panicked and attempted to kill Garwood, Powell shot him dead and buried him. The box was empty, as Powell had kept the money in his own safe.
Powell killed Garwood to prevent him being questioned and potentially implicating him. As Powell's wife was left mentally broken by her son's death, and completely reliant on Powell, he kills her and himself to avoid arrest. Frost learns that his wife has died while he was working. He reminisces with her nurse, Shirley Fisher, admitting that they grew apart after learning his wife could not have children. She re-focused on living a better life instead, and could not tolerate Jack's slobbiness and lack of ambition, resulting in him spending more time away from home, and eventually starting an affair.
Frost was going to leave his wife before learning she had cancer. Dismayed, he got drunk and later subdued an armed criminal, hoping he would be killed, which resulted in him being shot. For his apparent bravery, he received a George Cross medal, finally making his wife proud of him. DI Frost finds himself coping with a shortage of officers, due to an illness circulating the area, and the sudden arrival of his late wife's overbearing sister, as he handles two investigations.
