A teenage boy is found badly beaten, and a young girl, Lisa, from the same school is missing. DC Webb shows little interest in the case, so Sgt Cryer investigates the girl's disappearance himself. A local 'photographer', Andrew Morton, is the main suspect, as he has an obsession with Lisa and her friends, and he is arrested when PC Harker spots him acting suspiciously by the canal. When Lisa turns out to have been hiding out at a friend's house the whole time, Cryer must rush to prevent Lisa's father from taking the law into his own hands by killing the innocent Morton.

DC Webb and DC Riley wait outside a cafe, whilst inside DS Debbie McAllister is conducting a rather clumsy undercover sting on a suspected drug dealer. DI Cullen is furious when the suspect is released without charge following McAllister's poor handling of the case. Resentful of DS Singh's success in recruiting local informants, McAllister manages to coax some information from solicitor's clerk Jamie Ross, which eventually leads to a successful arrest when Ross's information blows apart a stabbing suspect's alibi. Pleased with her success, McAllister is determined to convince Ross to work as an informant for her. Meanwhile, DC Paul Riley meets up with his brother Joe, who seems to be in some trouble with the Nottingham police.

CID investigate a spate of car thefts, and DS McAllister's informant Jamie Ross gives her a tip-off about a gang of French car thieves working in the area. Ross is reluctant to name his contact though, who turns out to be Joe Riley, DC Paul Riley's brother. The gang is arrested, but are broken out of Canley Crown Court by a trio armed with shotguns. An SO19 raid on Joe Riley's lock-up sees them in custody again, but DC Riley must work hard to hide his brother's involvement, particularly as Ross informs McAllister that it goes deeper than Riley thinks.

PC Worrell and PC Quinnan attend to a woman threatening to jump off a bridge. She turns out to be Sarah Collins, the wife of Terry Collins, a DS at Stafford Row CID. Despite the doubts of some of her colleagues, PC Worrell is determined to pursue the matter as a domestic violence case. She convinces Sarah to make a statement and testify in court by telling Sarah of her own experience with domestic violence. The case is dismissed, however - Sarah becomes reluctant to testify, and there are doubts about her character. When Worrell goes to check on her at the Collins house, she finds that Sarah has murdered her husband. Meanwhile, Dave Quinnan struggles to find the right time to tell his wife about his affair with Polly Page.

A young Russian girl leads Dale Smith out of a nightclub, where he is promptly attacked by three men. Despite Smith's protests, Supt. Chandler assigns DI Cullen to investigate the assault. They track down the Russian woman, Natasha Ivanova, through a language school which seems to be recruiting students to work as prostitutes. Natasha is desperate as her visa is about to expire, and her sister has disappeared. Her sister is found murdered, and Smith realises the men responsible for her death and his assault are linked to a man from his old army unit (episode: Blurred Around the Edges).

Hoping it will convince Supt. Chandler to endorse his transfer to SO19, PC Smith volunteers with PC Klein to 'babysit' Clive Allein, the victim of a gay bashing who is reluctantly testifying against his assailant, Gary Cook, in court the next day. Smith nearly blows it when his angry reaction to Clive's partner Ian Jones's teasing causes Jones to run off, where he is promptly attacked, and Allein refusing to testify, until Smith convinces him otherwise. The trial goes ahead, and the attacker is found guilty, but further threats from Cook's friend Paul Taylor cause Ian to storm off again, this time he goes missing. Smith and Klein fear the worst when a stabbing victim is reported, but it turns out to be Paul Taylor who is the vicitm, and Ian Jones the attacker.

Supt. Chandler is speaking at a meeting on the Larkmead Estate, but vandalism and a petrol bomb cut short his talk. Sgt. Ackland is called to the house of local MP Stephen Hadley and his wife Fiona, where their infant child has died of serious injuries. Forensic examination reveals the baby was thrown to the floor, and Fiona Hadley says her husband was responsible. Hadley is arrested, but denies her claim. A lack of evidence sees him released, but he is arrested again for beating his wife when he returns home. It turns out the Hadleys' other child knocked the baby's high chair over.

After an ear-bending from Marsha Harris, Supt. Chandler is determined to bring to an end the one-boy crime wave on the Larkmead Estate caused by resident hooligan Peter Rogers. Chandler persuades Sgt. Ackland to talk to Peter's mother, and also tries to get Marsha Harris's daughter Cassie to make a statement to the police against Rogers, but both are too scared of the boy to comply. When Cassie Harris is found half-drowned in a river, and PCs Stamp and Hollis turn up a CCTV tape of Rogers smashing up cars, it seems they may be able to put him away at last - although it turns out that Cassie's drowning was self-inflicted and the CCTV tape is actually Peter's brother Gavin trying to frame him for criminal damage.

DS McAllister continues to get useful tip offs from her informant and lover, Jamie Ross, including one about an armed raid on a betting shop. Meanwhile, there's a war brewing on Sun Hill turf between rival hot dog vendors, one of whom is DC Paul Riley's brother Joe. When Joe Riley's lockup is set on fire and several of his vendors attacked, PCs Hollis and Hayward and DC Riley go undercover as hot dog vendors to catch those responsible.

DS McAllister pushes her informant and lover Jamie Ross too far when she tapes a privileged conversation between Ross and a client who admits to intimidating a witness in a court case. When Ross makes an official complaint against her, she turns to DC Riley for help and threatens to expose his cover-up of his brother's involvement with the French car gang unless he backs her up and says that he was present at all her meetings with Ross.

DC Webb poses as a 'rent-boy' in Eddington Park, a well-known gay beat in Sun Hill, as he and DC Lennox investigate a series of brutal attacks on gay men in the area. A car alarm alerts Webb and Lennox to the car of a local MP parked in the bushes. When questioned, the MP claims he was car-jacked and certainly was not 'cruising' in the park. He threatens legal action and Supt. Chandler moves quickly to prevent further damage to Sun Hill's reputation. A helpful security guard offers the police an observation post in a nearby office building, but Webb is suspiscious of the guard's attitude.

DC Kate Spears is assigned to a domestic violence case, but is alarmed when DC Mickey Webb realises the perpetrator, Neil Hayes, is also a suspect in a series of truck hijackings he is investigating, and requests he be bailed so he can lead them to the gang. Spears's sympathy for the victim, Lisa Hayes, starts to wear thin when she refuses to press charges, harasses Spears at work, and then is discovered to be having an affair with Hayes's boss.

Supt. Chandler is outraged when he finds out about the aggrevated burglery of a deaf and blind woman in the local paper rather than from CID. Reg Hollis overhears Matt Boyden gossiping to Vicky Hagen about Dave and Polly, and soon the news of their affair is all over the station. Accompanied by a reporter from the newspaper, CID and Uniform raid the house of suspected burgler Mick Corcoran, but when Corcoran attacks Polly Page, he is brutally beaten by Quinnan and requires hospital treatment. Sgt. Boyden arranges tickets for a charity ball, but the limo breaks down and they all take refuge in a country pub, where Jenny Quinnan finally works out that Dave is having an affair.

Dave Quinnan arrives late after rowing with Jenny all night. Ever the troublemaker, Sgt. Boyden sends him out on patrol with Polly Page, Tony Stamp and Vicky Hagen. Quinnan and Page have trouble keeping their mind on the job, and this gets dangerous when Stamp is attacked by a gang of thugs on the DLR and Quinnan is nowhere to be seen. When Jenny leaves him and returns to Dublin, Dave starts to crack up. He puts on his uniform after his shift and goes on a vigilante mission to find the gang responsible for the attack on Stamp. DC Webb gets an anonymous call and finds some of the gang members tied up and sprayed with pepper spray.

Dave Quinnan just stands and watches as a shopkeeper and a young woman are attacked by a gang of thugs at his local corner shop. When he finally turns up at the station, he identifies the leader of the gang as Robbie Gaitskill. Polly Page turns up in tears, and she and the rest of the relief are concerned as Dave seems to be cracking up. The crackheads arrested the previous night identify Quinnan as the policeman who attacked them. As Hagen and Page try to find him, Quinnan goes AWOL and tracks down the woman from the shop, Tricia Martin, and demands she tell him Gaitskill's address. Half the relief turn up on Gaitskill's doorstep, only to find Quinnan sitting in a car outside. Gaitskill is arrested, and Quinnan is told by Supt. Chandler to take his sick leave and seek professional counselling.

When DC Lennox is accused of planting evidence in an armed robbery case, DCI Meadows is determined to charge the suspect's accomplice, Phil Brown. Unfortunately, Brown claims to have been an informant for DS Don Beech, which makes Supt. Chandler determined to drop the case. When an old friend of Meadows' reveals that George Stubbs had previously bribed Chandler's DS at Park Rise, Meadows realises he has some ammunition against Chandler. Meanwhile Sgt. Boyden and PC Hagen help PC Roz Clarke recover her ASP when it is stolen while pursuing a robbery suspect.

Under pressure from Supt. Chandler and the NCS to release Phil Brown, DCI Meadows convinces Moira Scott to admit to George Stubbs's involvement in the armed robbery as well as drug dealing. DC Kate Spears goes undercover as a cocaine buyer, and with some help from NCS and SO19, they catch Stubbs and his supplier red-handed with the drugs. During his interview, Stubbs makes an allegation of corruption against Supt. Chandler. Before he calls in CIB, DI Cullen convinces Meadows he's only been told half the story.

PC Jim Carver attends to a drug dealer found badly beaten on the Larkmead Estate, but finds himself in a dilemma when a friend Ossie from his AA group confesses to the crime. DS McAllister follows Carver when he tries to convince his friend to turn himself in, and to his horror, Ossie is arrested shortly after. Carver realises that Ossie had suffered an alcoholic blackout at the time, and that the real beating was committed by a rival drug dealer on the Larkmead. Meanwhile, Uniform contend with the BIC gang, a group of youths harassing local shopkeepers.

PC Roz Clarke is on attachment to CID, and puts up with the usual teasing from the detectives and her uniform colleagues. She cracks the case she is working on with DC Glaze though, when she realises that a series of break-ins are all one surname in the phone book. When Ch. Insp. Conway and DI Cullen attend a rugby match between the Met and the Army, Conway is abducted when a disgruntled soldier decides to take revenge on those responsible for the abuse he received while at a children's home.

PC Smith and PC Klein attend to Mr Kennedy, whose house and garden shed have been attacked by vandals repeatedly over the past few weeks. When Kennedy threatens to take matters into his own hands, Smith casually comments that he wouldn't blame him if he did. Smith and Klein both apply for new jobs - Smith submits his application to SO19 and Supt. Chandler wants Klein to take the position of partnership officer at the Town Hall. When Kennedy shoots a young boy, and insists that PC Smith told him to do so, Klein reluctantly confirms what was said, and Smith accuses him of grassing him up. After attacking Klein in the corridor, and under investigation by CIB, Smith is suspended from duty.

PC Klein is offered the position of partnership officer, but he is shunned by the relief, who think he grassed Smithy up to get the job. Sgt. Cryer has a funny feeling about Frank Kennedy, and decides to do some digging of his own, and he encourages Smith to do the same. With Klein's help, Smith infiltrates the gang of youths intimidating the local residents, and discovers that the real estate firm Mather & Devine is indeed behind the harassment. Meanwhile, Cryer uncovers the fact that Kennedy was a notorious East End gangster named Ken Franklin who stored weapons for the Kray brothers, and that Kennedy's claim of shooting in self-defence is disproven by the forensic evidence and a statement from the other gang member. Smith is re-instated, Supt. Chandler approves his transfer to SO19, and Klein turns down the partnership officer job.

Sgt. Bob Cryer is approaching his 30th year of service, but some of the senior officers at the station doubt he is still up to the job. Supt. Chandler assigns Cryer the difficult task of resolving a situation where a group of prostitutes are at loggerheads with a local residents group led by Counciller Angela Morris. Cryer suggests a 'zone of tolerance', a non-residential area where the prostitutes can work without upsetting the locals, and manages to convince the girls to give it a try. As Chandler heads off to a charity dinner, a call comes through that the Morris' house has been torched. Meanwhile, PC Smith attends his interview for transfer to SO19 - he is successful, and leaves Sun Hill to join the Armed Response Unit.

When the victim in yesterday's domestic disturbance turns up badly beaten and left for dead, her husband is adamant he had nothing to do with it. Mandy tells Cryer that the woman who was bashed, Cath Evans, was working as a prostitute, and that the Councillor's husband Justin was one of her clients. But Justin in turn, having admitted his deeds to his wife, says that he was seeing Mandy as well, and that on the night of the fire, she turned up late and had blood on her clothes. Meanwhile, Smith arrives at SO19 to find his new friend Julie also made the grade, but on their training course, treats her as the token female. When she beats him on the rifle range it causes friction, and their boss cautions that they have to learn to work as a team.

PC Nick Klein becomes involved when Kosovan refugees housed at a council estate are being harassed and attacked. Later, at a family gathering, Nick's cousin Jerry arrives and is praised by the family for his success. DC Webb investigates a robbery at a clothing factory, and his investigations lead him to Norman Klein, Nick's uncle. The link between the latest robbery and a previous one is revealed to be Jerry Klein who assessed security at both places. When Jerry is found badly beaten, Nick decides he must tell the police about his cousin's possible involvement, which results in DI Cullen catching the gang on their third job.

Sgt. Cryer and PC Hayward attend an incident at a local school where an angry divorcee, Chris Finnessey, is demanding to see his son. When the boy's teacher warns the police of Finnessey's violent reputation and a possible restraining order against him, he grabs a Stanley knife and takes the teacher and Sgt. Cryer hostage. Faced with an armed suspect and two hostages, Supt. Chandler calls in SO19, although the only Trojan unit available is that of the newly-qualified PC Smith and PC Stanley. When Finnessey and his son leave the school building, Chandler gives authorisation to fire. Smith shoots first but to his horror, accidentally hits Cryer. Stanley takes down Finnessey. Cryer survives the shooting, but his career in the police is over.