DI Chappel has to sacrifice his new relationship to save Sgt Robinson from the murder accusation.

Desperate to crack the Eastern European sex-slave ring, DI Chappel betrays an old friend, with deadly consequences.

The Vice Squad investigates a massage parlour where Eastern European girls are being forced to work as prostitutes after being illegally smuggled into the country. Sgt Robinson's marriage gets emotionally involved with a witness.

DI Chappel and PC Hutchins work undercover to investigate the gambling operation at The Jupiter nightclub.

DI Chappel goes under cover as a lodger to investigate a suspected porn merchant, but PC Hutchins discovers the house is the base for a paedophile ring.

Chappel resolves to resume his relationship with Jane, now working as an escort, but the corrupt DS Vickers is sniffing around her too.

The investigation into the escort business is jeopardised when PC Raymond takes his interest in prostitutes to a personal level. Chappel investigates the blackmail of a new life peer.

Chappel's efforts to bring down the illicit gambling and prostitution organisation pushes PC Raymond to the brink.

The team have a well known and high class pimp David Hinkley under surveillance, but fail to save one of his girls being murdered. His daughter Natasha hides the envelope which contains the evidence needed to charge Hinkley. Nikki a working girl is looking for help from Chappel. He attempts to persuade her to make a statement about Hinkley. For her troubles she will receive a room in a hostel, but Nikki declines. Hinkley is bailled due until further enquires. He visits Nikki, believing she informed the police. Unknown to Hinkley, Natasha has already arrived there to do the same. Nikki and Hinkley fight, Natasha hides herself in the bathroom. Hinkley in a rage pushes Nikki out of a first floor window, an action witnessed by his daughter, Natasha. The murder squad are now involved on the case, much to Chappel's disgust.

Nikki is in hospital recovering from her ordeal, receives a visit from her ex-pimp, Guy Walsh. Walsh killed the prostitute after he discovered that she was recruiting his girls to work for Hinkley. Natasha is fazed by what she witnessed and doesn't know what she should do. Walsh pays a visit to Hinkleys home but finds Hinkley gone, he abducts Natasha as a bargaining tool. Hinkley has to pay Walsh a generous amount of money for his daughter back, Hinkley trys to negotiate but fails. Nikki has been discharged from hospital and moves in with Walsh and finds his prisoner. The Vice squad find Hinkley, he informs them what has happened with Natasha and what kind of man Walsh is. Chappel goes into the flat pretending to be a punter, Nikki tells him where Natasha is. Natasha is freed and Walsh is arrested.

DI Chappel runs into former boss DS Frank Vickers in a Soho brothel, past secrets are unearthed that threaten to destroy both the vice squad and Chappel's personal life. Investigating the death of a prostitute, Chappel tries to enlist the help of an ex-girlfriend, but she has moved on from the sex trade.

Chappel is at court for the trial of a prostitute accused of murdering her pimp. Girlfriend Jane loses her job with an investment company and decides to go back to the vice trade. DS Robinson strikes up an inappropriate relationship with PC Morgan.

WPC Hutchins takes on more than she can handle while working under cover, when she discovers that a night club boss has a side line in S&M films. This also brings back painful memories to her boss Pat Chappel.

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