Part One: Weston leads the hunt for a missing baby girl. The nanny is pressed on her whereabouts when they discover she wasn’t at home, and when a note left on an IRV points them to her boyfriend, he is put in the frame. Stamp is assigned as FLO, but he is put in an awkward position when it appears the mother’s young niece put the note on the IRV. When another suspect comes into the frame, CID unearth an illegal adoption agency, but the baby found in the car of the suspects is a boy, leaving CID running down a blind alley. Further digging into the nanny and her boyfriend leads to a major development in the case... one that none of the team wanted.

Part One: Brown and Ryder investigate the disappearance of a teenage athlete. When he is found dead, connections are made the collapse of a teenage girl at a party that Armstrong and Stamp break up. The girl is revealed to be the boy's girlfriend, but she can't be interviewed while she is unconscious. The boy's friends come under fire, including a local drug dealer, but when he is cleared, two other friends come into the frame.

Part One: Valentine and Ryder are first on scene when two boys discover human remains buried in a local park. Olosunje determines the victim, Susan Clark, was buried in 1988. Weston runs into former park-keeper Arthur Hurst, who goes from witness to suspect when Susan is revealed to have had a run in with him not long before her death. The family are implicated, when it is revealed Susan had a relationship with her stepbrother Andy, who is found drunk at the scene. Just when it looks like someone in the family could be involved, Heaton uncovers a link to a villain from his days as a DC, blowing the case wide open.

Part Two: With CID hitting a brick wall in the investigation to the death of Susan Clark, Heaton interviews jailed murderer Ian Ellis. When another missing person is revealed, Heaton arrests him for Clark's murder. When the third body is found, Ellis goes on hunger strike and dismisses his solicitor, leading Heaton to come under fire.

Part One: Carter investigates when an apparent case of vandalism turns out to be a protection racket within the Polish community. Nixon is furious when she discovers the main suspect, Marek Jankowski, is the brother of Thomas Jankowski, a man Carter killed during his CO19 days. Carter forms a bond with Thomas' wife Julie, and convinces her to set up Marek for a cigarette lorry highjack. However, tragedy strikes when Marek realises he’s been set up.

Part One: Green investigates when her attempts to talk a girl down from a bridge fails, leading Roberts to heroically dive into the river for a daring rescue. Green uncovers a blackmail at the gym where she works, but clashes with Perkins over his heavy-handed tactics in interview, causing the girl to lose faith in Green. Green also asks Stamp for advice when she applies for a post at Witness Protection, while Nixon offers to help her by speaking to a friend who works there.

Part One- Back to School: Roberts is assigned as Safer Schools Officer to Deansgate Comprehensive after a fire in the art department. After a fight over a stolen iPhone is broken up, another is arranged, so Roberts enlists the help of Smithy, only for the Sergeant to be left fighting for his life after a stabbing. Drugs come into the equation, and Weston launches a raid when a burglary victim points out one of the yobs involved in the stabbing.

Part Two- Learning Curve: Roberts, newly appointed Safer Schools Officer, uncovers drug abuse at Deansgate School. When a huge bag of ecstasy is discovered, he and Masters investigate a connection between a student and a drug dealer.

Part Three- Peer Pressure: Roberts responds to a report of a break-in at the home of one of the pupils at Deansgate School. Masters discovers that the house was broken into by a fellow pupil who sought revenge for the alleged rape of his younger sister, and Roberts is put under pressure to find some answers.

Part Four- Growing Pains: Roberts breaks up a fight between two adults outside Deansgate School. Masters and Fletcher investigate the subsequent assault of one of the adults, a parent of a pupil at the school, and discover that he is the victim of a slanderous campaign following accusations of rape.

Part Five- Class Action: Roberts and Ryder investigate a break-in at Deansgate School, and are then called to the home of Roberts' close friend and art teacher Becky James, who has been seriously assaulted. Roberts and Banksy uncover a connection to an ex-convict, who is interested in a laptop belonging to James.

Part One: Gayle, Armstrong and Smith attend an armed robbery at a toy shop, with the manager shot during the raid, but a pursuit fails to prevent an escape. Carter takes charge of the investigation, and CCTV footage appears to show two known thieves casing the shop the day before. Carter suspects that a woman seen arguing with an employee moments before the robbery was acting as a decoy, but while Brown is convinced of her innocence, the rogue DS is only interested in undermining her opinion.

Part One- Full Throttle: A robbery at jewellery shop leads CID to an escaped convict on the run for murder, Manson sets off to find the killer, and tasks Carter and Moss with the investigation into the armed robbery, but could there be a link between the two crimes?

Part One- To Live For: Nixon tells Heaton she is transferring to the Child Exploitation Team at the end of the following day. Aiming to go out in style, she tasks CID with arresting suspected drug runner, Maloud Senac. Moss, Fletcher and Perkins observe his restaurant, and Moss recognises an old informant, Kenny Bordmann. He gives info on a drug shipment coming in from Cape Town. Moss discovers Senac's daughter Salma is in a relationship with freight owner Daniel Pfeiffer, the firm importing the drugs. A raid is launched, however the team only find a crate of pineapples. With Senac bailed and suspicious of his inner circle, he sets about keeping the police out, leading to two major incidents that sidetrack the drug importation investigation.

Part One: After an assault on a woman outside a PCP lab, Webb encounters Benjamin Meadows, the victim's boyfriend, with the DCI completely unaware that his son has been released from prison. Ben tells Webb that he is trying to get on his feet, but Meadows finds and arrests Ben when he is caught dealing on a local estate. Ben agrees to set up his dealer, Linton Barry, who Meadows suspects is working for Danny Travis, a dealer who is on the same wing Ben was on at Longmarsh. The deal goes pear-shaped when gunshots ring out.

Part One- Cover Up: Smithy investigates an assault outside the E1 nightclub. A watch is found in his pocket, and connections are made to a burglary Stone attends. Bar owner Jason Devlin becomes prime suspect in the assault, as the victim was flirting with Devlin's girlfriend. The burglary appears to be falsified as the assault victim is the burglary victim's brother, and that he was given the watch for a debt. With witnesses intimidated, including a cab driver, whose vehicle is torched, the case falls apart. The case takes a dramatic turn when a fire breaks out at the E1.

Part Two- To the Limit: CID investigate the arson on the E1 bar. Stone, Smithy and Carter suspect Jason Devlin is behind the arson, to get pay back on his bar manager for informing the police about an assault the day before. The Fire Investigation Officer finds fake documents in the roof of the manager's flat above the bar, where the fire started. Devlin is alibied, so CID look at his girlfriend, who is a suspected illegal immigrant.

Part Three- Breaking Point: Smithy and Gayle see a driver abandon a lorry containing illegal Afghani immigrants, leading to two deaths. With unrest on their estate, Smith is furious to discover Jason Devlin is the landlord for many of the immigrants, and may be behind the human trafficking. In attempt to win the trust of a suspicious community, Smith visits a refugee centre, but a riot breaks out on the local estate when Devlin shows up to evict the tenants.

Part Four- Walk the Line: Smithy is told by Stone he shouldn't confess to his assault on Jason Devlin, as Devlin will go down for his assault on Moss. From her hospital bed, Moss tells Fletcher that Devlin has a suspicious bag in his car boot, and that she was assaulted trying to look into it. When it is found full of stolen jewellery, Meadows and Manson suspect he is trafficking ringleader . Smithy uses Ara Byat to get her boyfriend, a Devlin associate out of fear, to testify against them.

Part Five- Riot City: Weston leads her team on a public order training exercise after the disastrous riot where Valentine was snatched and Moss was assaulted. Smithy and Stone clash over recent events, while Meadows and Manson deal with the allegations against Smithy. Heaton reveals that he is to leave Sun Hill to head a specialist unit dealing with human trafficking, and makes a generous offer to Meadows. A witness to Smithy's attack on Devlin comes forward.

Part One: Stone and Gayle come across the teenage victim of a serious assault. Stone sets off in pursuit of a suspect, who steps into the road and is killed. Manson and Dasari investigate the original assault, while Banksy is assigned as FLO to the victim's family. Manson tries to open up the mother of the boy involved in the fatal crash as she determines to prove he was not guilty of the assault, however they soon discover he wasn't as innocent as they thought, but a separate crime he committed clears him of the assault. With no leads, a huge twist in the case comes as they investigate the boy's brother, who points them in direction of a witness in the fatal crash.

Part One- Psychiatric Help: Valentine, Ryder and Taylor go to the aid of a young boy found abandoned in a busy market. Manson and Dasari discover that the boy has witnessed an assault on his nanny. Manson discovers the key witness is psychiatrist Dr. Julia Bickham, who had her patient Michael Simms shot dead on Manson’s orders in 2007. Meadows questions Manson’s judgement, but he ends up with strong evidence suggesting the attack was as a result of mistaken identity, noticing that Julia is the spit of the nanny, and drives the exact same car.

Part One- Trust Me: Perkins and Banksy set up an OBBO on an address where drugs are being delivered. The drugs are seen being delivered, but when Carter sends in a bust squad, he discovers the drugs have vanished. Masters meets an old informant, Fran Morris, who claims to have flushed the drugs for her flatmate, who stole them. Suspecting Fran is lying, Masters tasks Armstrong and Valentine with searching a rubbish chute, and their suspicions are proved correct when they find the heroin. As Fran agrees to setting up the dealer, it appears the suspected dealer's solicitor is the ringleader.

Part One- Invisible Man: Webb and Banksy attend the scene when the body of a young solicitor is recovered from the River Thames. Dasari becomes convinced that the man's fiancée is hiding something. The deceased had been volunteering at a local shelter, and Webb goes undercover as a homeless person to pursue the investigation.