The return of the series exploring the rising number of assaults on police officers. PC Mike Davey and his police dog Bacca are faced with a man armed with knives. Meanwhile in London, a routine car stop late at night suddenly turns into a life-threatening incident when the driver jumps in his car and drives off and PC Nick Morley is left clinging to the car door.

In Southampton, a Friday night in town descends into violence, and Sergeant Nicolas Tucker is left helpless on the floor after he is punched. Elsewhere in County Durham, PC Caryn Fairburn is on shift when she and her colleague are asked to respond to an argument.