Supt Susan Blake returns to work from maternity leave. For PC Steve Traynor the day starts rather differently. Within the station, as the news spreads of their colleague's injuries reaches the officers, emotions are running high.

The day starts badly for Steve - he has slept through his alarm. His concerned colleagues have to break into his flat to get him up for work. The team responds to a call about a till snatch from a newsagents.

Bill faces a life-or-death situation when he and Steve chase two men who have broken into the home of an antiques dealer, and Jim Oulten faces financial and marital problems.

Steve and Larry go undercover to catch muggers and Steve finds himself facing an old woman with a submachinegun; a pregnant woman makes a confession to an off-duty Susan; Connie puts her career ahead of a family life; and Steve narrowly escapes being blown up by a hand grenade dropped by the old woman whose husband collected war memorabilia.

A past case comes back to haunt Susan, but it is Jim who makes a grave error of judgement, which puts a suspect and his daughter in danger. Meanwhile, Steve continues his reckless behaviour and hopes to cover up that he has crashed a squad car in a high-speed chase.