Nursing his terminally-ill wife, Det Insp ""Jack"" Frost's life becomes more stressed when, during a missing-child investigation, he unearths evidence on a 30-year-old case involving a skeleton chained to a locked strongbox that turns out to be empty.

Frost investigates the murder of a teenage girl, and the case of a woman who has been receiving threatening phone calls. Meanwhile, at the Denton police station, there are threats, deaths, arson and a staff shortage.

Frost investigates an MP's son who is involved in a hit-and-run accident, and a robbery at a private casino, which occur on the same night. He gets a humorless new partner to assist him.

Frost investigates a series of break-ins and brutal attacks at the homes of elderly people. He is helped by a female detective, DS Lawson, who also offers him advice on his personal life.

Upon investigation, Frost discovers that the apparently accidental death of a drug addict was actually murder. He also decides to confront an aspect of his own past.