The Vice

Chappel goes undercover as an insurance-broking lodger to investigate a suspected porn merchant, who makes a sideline in dirty movies whilst running his own above-board video rental shop. However, when he learns that the residence is in fact the base for a paedophile ring, the case is recategorised and taken from Vice, leaving Chappel furious upon discovering that the case has been handed to Robinson – his first assignment since his promotion to Inspector. Meanwhile, as Hutchins begins questioning her loyalty to Chappel, the latter—unable to continue allowing the repeated abuse of a 12-year-old girl—attacks the prime suspect, eliminating any chance of bringing down the ring.

Chappel is delighted when retired prostitute Clara comes forward and offers to give evidence against Keith Beaumont, a former porn baron whom Chappel suspects is still operating. However, past encounters with Beaumont begin clouding his judgement and enthused by her boss' take on the task, Morgan offers herself as bait in a dangerous undercover honeytrap. Suspecting that Morgan may well have slept with Beaumont, Robinson persuades his new boss to allow him a week's secondment back to Vice to give Chappel a hand in his quest to prove Beaumont's guilt.

When prostitutes are murdered in the financial heart of London, Chappel reaches out to working girl Sandra, warning her to stay away from the unit's prime suspect, arrogant financier Gordon Ellis. Chappel uncovers a link between the murder victims and Ellis, but Hutchins isn't so sure that CCTV footage supposedly capturing the second victim with Ellis is concrete. As Chappel grows dangerously involved with Sandra, he becomes obsessed with nailing Ellis, and sends PC Kirsty Morgan undercover in an attempt to prove his involvement. Meanwhile, a sceptical Robinson receives news of his promotion, and announces he is leaving.

Chappel hopes to resume his relationship with Jane despite her descent into prostitution, but his plans are threatened when Vickers begins sniffing around. The team are visited by DC Damon Hills, who informs Chappel that he suspects Vickers of being bent, and wants to bring him down by whatever means possible. Using Hills, Chappel sets up a secret sting operation, soon realising that not only is he being double-crossed but Vickers has sent Hills to trap him. Determined to give his enemy the treatment he deserves, with Jane's help, he invents a fake, but believable, rape claim in order to ensure that Vickers goes down for as long as the law will allow.

Chappel goes undercover in a prison for sex offenders in order to flush out the ringleaders of a prostitution racket, which involves both the inmates and the prison staff. Reports suggest that inmates are being threatened with violence unless they allow the ringleaders to have group sex with their wives and girlfriends. However, it turns out to be a far more sinister conspiracy. Robinson, unhappy with the situation, tries to get Chappel out, but being so close to collecting the vital evidence, Chappel decides to stay undercover. Posing as Chappel's girlfriend, Hutchins is targeted, while Chappel's behaviour becomes increasingly erratic.

Attending the trial of a prostitute accused of murdering her pimp, Chappel tries a little gentle persuasion in an attempt to get the prosecuting barrister to press harder to gain a conviction, unaware of his own personal troubles. When the barrister is caught with a prostitute in a car park by Cheryl and Kirsty, he uses the excuse that he is 'gathering first-hand research' for Chappel and is let off with a caution. However, when caught again, Chappel realises he's unleashed a more dangerous beast than he ever could have realised. Meanwhile, Joe and Kirsty start to develop an explosive relationship, and when Jane loses her new job and goes back on the game, Chappel soon has new problems.

Chappel's former boss Frank Vickers is found lurking in the basement during a raid on a Soho brothel, and the team learn that Chappel has a more-than-shady past involving former prostitute Jane Farrell, with whom he fell in love. Vickers is determined to clear his name, and Chappel's life looks set to be blown apart when Vickers reveals some very sordid secrets to his colleagues in Vice. Chappel goes in search of Jane, and discovers that one of her friends, whom he was friendly with, disappeared some years previously and has never been found. When Chappel finds the body in the basement of the brothel, he becomes determined to prove Vickers' involvement in her death.

With Robinson's increasing aggression and temperament, it seems to paint him the prime suspect. However, Chappel believes otherwise and sets out to find the real killer.

Robinson and Hutchins are on a stakeout, watching a violent pimp suspected of attacking one of his girls. When the pimp confronts him, Robinson, still wound-up from the last case, as well as the impending collapse of his marriage, attacks the john in front of several onlookers. When the pimp is found murdered the next day, the blame is soon directed to Robinson's door, with evidence of his run-in from the day before.

Chappel assigns Joe Robinson to the case, unaware that the girl is actually harbouring feelings for Robinson. When his wife Shirley becomes suspicious of his interactions with the girl, Robinson finds his marriage on the rocks and the impending pressures of the job becoming too much. Chappel is forced to find new evidence after the girl reveals that she's pregnant and no longer willing to testify.

When the team raid a brothel operating as a massage parlour, they discover that the young female employees have been smuggled into the country from Eastern European refugee camps. One girl offers to testify against the ringleader, but only if she is given round-the-clock protection.

When Raymond falls hopelessly in love, he attempts to woo the one particular girl into a real relationship, instead of a business arrangement. However, when she subsequently leaves the country to traffic drugs, Raymond goes on the rampage and jeopardises the entire case... and his career in Vice.

Tasked with investigating an escort agency who are providing a sideline in drugs trafficking and prostitution to their more than satisfied customers, Chappel sends PC Dougie Raymond undercover as a punter to gather evidence. Dougie successfully manages to secure the intel, but soon finds himself hooked on prostitutes.

Hutchins is making slow progress in her bid to find the young boy involved in a porn film, but believes his parents are hiding important information about his past. Meanwhile, Chappel's professional relationship with Dr Weir becomes personal.

WPC Cheryl Hutchins takes on more than she can handle while undercover, when she discovers that a nightclub boss has a side hustle in S&M films. This also brings back painful memories to Chappel.