The detectives are suspended after an incident with a suspect briefcase, a plan to nab an East End villain leads to a wager with a blind man, and Cottam prepares his men for the conclusion of an undercover operation.
A monk witnesses the murder of a man in the toilets of a railway station, Briggs tries to find someone who likes him enough to listen to him, and Cottam sends two officers on a protection job at a Cumbrian monastery.
Stories keep appearing in the press about a duchess sleeping with her bodyguards, Cottam cancels the holidays of two undesirable officers, and Briggs convinces himself that he's far too manly to escape her attention.
Briggs and Louis get trapped in a pilchard lorry while on duty at customs, a ferry takes them to what they quickly work out to be northern Italy, and diamond smugglers go in search of two men wearing sou'westers.
Cottam pays the price for his officers getting carried away during a mock riot, Briggs and Louis go undercover in a gym to investigate steroid use, and a disgruntled boxer grabs an opportunity to prevent another victim.
Volunteering to help with police dog training puts Louis in a wheelchair, Briggs wants to know more about a relationship with a girl on a horse, and reporting the murder of a neighbour proves to be a little tricky.
