Part One: CID jump into action when Roberts and Green witness an 11-year-old boy, Dean Clark, being abducted from a shopping centre. A clue left at the scene suggests a connection to notorious child killers Alistair Haig and Linda Johnson, but the former is dead and the latter is in prison. Manson visits Johnson with Turner; she isn't interested in helping, but later calls Manson and requests to see him alone. She tells him about her boyfriend, Mike Wilson, and explains they split and he claimed he would prove that he loved her. Wilson's flat is raided, and clippings from the original case are found plastered all over his walls. He confesses to murdering Dean when arrested, but the biggest twist is yet to come when Dean calls his mum.

Part One- Innocent Blood: Smithy reconnects with troubled mum Carly Samuels when she reports the stabbing of a local teenager, Tito Morientes. When she gives false info on Tito's attacker, Smithy discovers her boyfriend Marlon Reed is behind the attack, and he tries to convince her to help. CID stumble across an illegal renting racket run by one of the suspects in Tito's assault, while Roberts and Armstrong investigate a young boy who sets fires to relieve the stress of looking after his sick grandmother.

Part Two- Wall of Silence: A shock shooting sees Carly Samuels gunned down on the Jasmine Allen Estate, and she tragically dies of her injuries upon arrival to hospital. Smithy is assigned as family liaison officer to Carly's distraught mother Leanne, but it all goes wrong when a false claim Carly was a prostitute leads CID down a blind alley. Smithy offends Leanne asking her if the rumors were true, leading her to throw him out of her house. Carly's ex Dwayne Fox reveals Marlon Reed is a drug producer, but Dasari finds herself in the middle of a shootout as she tracks a vengeful Reed holding prime suspect Tito Morientes hostage.

Part Three- Breaking Point: Leanne Samuels continues to refuse Smithy's help as her FLO when she is found trying to confront Tito Morientes at his flat. She later tells him that her psychic friend, Dawn Stanley, claims Tito was seen entering the drive-by vehicle just before the shooting. Hollis discovers the psychic was somebody Stamp met after the death of his father, but Stamp’s reaction leaves her refusing to help. As Hollis and Green track down her boyfriend, an associate of Tito, Stamp apologizes to Dawn in an attempt to get her to open up. She reveals the location of one of the guns, but with her boyfriend's refusal to make a statement and CCTV inconclusive, Leanne takes desperate action.

Part Four- Deadly Secret: The day of Carly Samuels' funeral unfolds in chaos as Tito Morientes is arrested after firing a gun during a brawl at the procession. A dramatic revelation leads to an unlikely suspect, while a crucial witness comes forward naming Tito as one of the gunmen. Elsewhere, a series of robberies occur during the funeral, including Carly's. In addition to the hunt for the suspect, the Sun Hill team are left to contend with a group of vigilantes tracking the burglar. Manson takes leave to visit his son in Spain.

Part Five- Protection: Meadows launches the raid on Dwayne Fox's home, and Nixon coordinates one at Tito Morientes'. Tito is arrested, but Dwayne isn't home. Dwayne's mother Beverley breaks his alibi, but his boss kidnaps baby Brooke to increase the pressure on the team. Alisha Danniels’ phone signal puts her at the scene of the murder, and she gives another statement that reveals there was a third man in the car, turning the case on its head.

Part Six- Hit & Run: Alisha Danniels is left fighting for her life when she is hit by a speeding car after being taken home from the station. A chase ensues, but the car escapes down railway lines before being found on fire. With the fire quickly extinguished, there is hope for the investigators. The car leads to two investigations as Roberts and Keane try to track down a teenager who fooled the owner in order to car-jack him. When the boy's older brother leaves mid-interview, Alisha identifies him as the driver of the drive-by car. Refusing to give a statement, Dasari and Smithy discover Alisha's dad Oscar knows where he is. As part of the forensic check of the car, bullets are found in a hidden compartment of the boot, so Carter tracks the owner in order to bust him selling them on.

Part Seven- Truth & Lies: When the trial for Carly Samuels' murder kicks off, Dasari is surprised to find out that the defence barrister is her ex-boyfriend, Sunil Davdra. Key witness Joel Pearce folds after being threatened inside prison, causing Smithy to beg of Alisha Danniels to change her mind and come forward. Elsewhere, Masters and Moss investigate an assault on a pregnant woman, discovering it was ordered by her street thug boyfriend Raheem Woods. After smashing his face against a cell wall, Woods accuses Roberts of assault and is released. The cases cross paths when Raheem riles up the estate as Smithy, Alisha and Oscar leave for court, with all three left in danger.

Part One- Pay Back: An SUV owned by known criminal Dylan Morrison is involved in a chase and crash, but the driver is a young boy called Liam Harvey. He claims his father was threatened by Morrison, and the claim may be justified when his father is found in his crashed car with puncture wounds in his back. When Morrison is attacked and found with the word scum tattooed in his head, Gayle begins looking into Liam's mother, believing that she is the victim of domestic abuse. CID investigate Morrison's assault, linking it to a blackmail scam.

Green and Keane come on shift with hangovers. Their day starts badly when they turn up late to a briefing with the Super, covering uniform for investigations while CID work a fraud case. It only gets worse when Heaton volunteers to join the duo on patrol. Gold and Wright go to Canley Market, mainly so Gold can keep an eye on Heaton! Roberts and Valentine find an abandoned electronics van, and find the driver tied up in the back. Heaton freaks out a female drug dealer when he arrests her, due to a history of abuse. Green, Keane and Heaton find a young boy working his mother's stall, and two robots stolen from the van are found. The drug dealer, Rachel Compton, has her flat turned over, and her brother Matty is found assaulted, surrounded by several damaged robots. Green and Heaton find heroin in the back of one of the two they seized. Rachel's boyfriend, James Maguire, is suspect number one, and he is being hunted down by Jaz Desai, the van's owner, wanting his drugs, and he's holding Rachel hostage.

Part One: Keane and Valentine respond to a disturbance and find a teenager with her wrists slit. It appears she is being groomed as part of an online paedophile network. When her friend goes missing, CID launch a manhunt, with Perkins looking through offenders. Dasari is seconded to the Child Exploitation and Online Protection group to work with Detective Superintendent Tom Faraday, and tries to open up professional yet compassionate Detective Inspector Phil Ashley. Just when it seems they've busted the ring, a post by a user named "Domino Man", promises a live feed showing the abuse of an 8-year-old boy in 24 hours.

Part One: Gayle and Stamp discover the body of drug addict Abbey Ferguson in a derelict building, whilst searching for a distressed young girl, and the trail of evidence leads back to her pimp Danny Peters. A prostitute claims she saw the violent client dragged Abbey's body downstairs. When this turns out to be false, she is arrested and has to give up Danny. When it conspires he killed Abbey for not sleeping with the violent punter, he injected her with a large dose of heroin. As Moss and Turner confront him, he arms himself with a needle.

Part One: Smithy attends the scene of an assault on an elderly man. He turns out to be Johnnie Jackson, an ex-East End gangster and bank robber. When Smithy and Carter visit Johnnie, he is visited by his grandson, Jacko, and Johnnie claims he is dealing for Bosnian drugs warlord Andreas Audra. The team are perplexed why a gangster would 'grass' on his own family, but Johnnie points the team in the direction of a nightclub owned by Jacko and his love child Roger Hutton. As Jacko is implicated in a smuggling op, Johnnie hopes they can bring down Roger. Events take a sinister twist when Jacko is found dead in Johnnie's house.

R.I.P. P.I: DC Jacob Banks joins the Sun Hill watch in time to help a hung-over Webb investigate the murder of a private detective. It appears he was looking into the disappearance of a woman, Geraldine Lawson. When a witness is tipped off, her family suspect she is dead. A complicated case brings up a suspect, but he proves elusive for the CID team. Keane is left disappointed when Stone refuses to put through an application for her to go undercover on the case.

Part One- Shockwave: Keane and Armstrong are first on scene when two explosions tear apart a photocopy shop and a nightclub. Stone coordinates the efforts of officers from Sun Hill and Barton Street as they deal with terrified members of the public, while their efforts are side-tracked by an electronics thief and a sexual assault suspect taking advantage of the chaos on scene, and things only get worse when Heaton receives an apparent threat about a third explosive device. After weeks of disputing, Keane accuses Stone of being bent and storms off. Keane finds a office block on fire, and when a suspect package is found in the building, she heroically puts her life on the line to get everyone out safe.

Part Two- Aftershock: The relief remain in a state of shock after Keane’s death the day before. In uniform, Stone expresses his guilt to Gold before later unleashing his fury on Smithy. In CID, SO15 DI Karen Lacy comes in to head up the investigation. The first two bombings are linked to a porn racket, while Webb discovers the third bombing was targeting a racist businessman. An emotional Armstrong opens up to Stone over the loss of her best friend Keane, leading her to try and attack a suspect. When a bomb is found in his neighbour's back garden, Walker finds herself standing on a pressure pad that arms a bomb. Dasari makes a breakthrough that could be imperative to the case.

Manson returns to Sun Hill after visiting his son in Spain. He pairs with Moss and investigates an assault and disappearance involving a wedding groom. Manson finds himself being flirted with by a gay club owner, and arrests a Kylie Minogue impersonator, not without Moss grabbing a photo! The recently arrived DC bonds with her new boss when she realizes he had an indifferent visit with his son, with Manson overhearing that Turner bet Moss £20 that she could find something personal out about him. Morale in uniform takes another downturn when Gold reveals Hollis has resigned following the death of Keane, and she stresses the importance of recruiting new uniformed officers to Heaton.

Part One: Upon return to Sun Hill after going on the Undercover Training course, Green teams up with Armstrong. The pair find a man, Alan Marlowe, beaten up in an alleyway of a known red light district. CCTV shows him arguing with his stepdaughter, Lucy Burton. Burton is remanded in custody, but is quickly bailed. When her mother confesses to the assault, Burton intervenes and admits she assaulted her stepfather. She explains to Green that Marlowe attacked Lucy's mother for every time she tried to contact her, but her mother won't make a statement. Armstrong tells Green she thinks she got too involved with Lucy.

Part One- Trigger Happy: Banksy, Valentine and Gayle are first on scene when a young boy, Emile Grover, is found with a loaded gun. Banksy talks him down, and it is identified as an army-issued Browning high power pistol. Emile identifies the man who gave him the gun as Andrew Tyrell. Captain Charlie Shaw of the army identifies the owner of the gun as Corporal William 'Billy' Figgis. Conveniently, Figgis already dealt with Smithy and new PC Mel Ryder, but after holding them hostage with a replica handgun, he goes missing. Billy's wife, whom he'd been harassing, reports their son Josh missing. Billy is arrested on suspicion of abduction, but he reveals Tyrell is holding Josh so he can get more weapons. Events spiral when Henry Grover reports Emile missing, and he was last seen with Josh Figgis.

Part Two- Undercover: Suspected gun runner Andrew Tyrell mentions supplier Billy Figgis has been working with Kieran Wallace, a thug converting firearms for an as yet unknown kingpin. With nerve damage from the stabbing by Tyrell, Figgis agrees to introduce Smithy to Wallace. Smithy gets an in, and prepares to go deep undercover with Moss acting as his girlfriend as a way of contact. Meanwhile, after Roberts arrests a woman involved in a hit and run, Bansky discovers she was sexually assaulted in her home. The main suspect is a disgruntled ex-boyfriend, but after he is implicated despite having an alibi, it raises the question, who'd agree to rape someone for a friend?

Part Three- Kick Off: Derby day; the Sun Hill relief find themselves on security for the Millwall vs Leyton Orient game at The Den. With Smithy attending alongside Kieran Wallace, uniform find another issue; a stolen case of volatile fireworks being set off by kids. With rival intelligence claiming the Orient fans would welcome the home fans with a bang, uniform have to go all out to find the rest. Smithy loses his cool with one of the gang, which impresses ringleader Darren Cutler. Gold goes into meltdown when Ryder is nearly killed when the vehicle full of fireworks explodes, but she carries on when she & Fletcher have to take a woman in labour to hospital in the transport van.

Part Four- Spray and Pray: Smithy finds himself holding a gun that Wallace claims was used in a shooting. Moss recovers the gun, but Smithy spends the entire day concerned his cover is blown. Carter suggests setting up Wallace to plant the gun, and when Wallace is arrested, Smithy finds himself looking down the barrel of Cutler's gun. He is also introduced to Bob Gatting, the boss of the SE1 gang, organising security and cash for the deal. Cutler meets the supplier under surveillance at his workshop. Meanwhile, CID use the gun to investigate the murder of an ex-con.

Part One- Blind Alley: A young woman, Paula Merrick, is found unconscious in an alleyway. During a chase by Roberts, the suspect drops a stun gun, and signs suggest she was raped; Nixon takes charge of the investigation. Nixon's suspect is male stripper Tom Norris, but forensics aren't strong enough to charge him with rape, as he claims he had sex with Paula. Meanwhile, Fletcher’s first job on attachment to CID sees him paired with Perkins to look for a supplier of the stun guns.

Part One: Whilst on operation at the docks to arrest thieves, Meadows is stopped by Karen Lacy, now an Intelligence Officer with the Serious and Organized Crime Agency. She convinces Meadows his theft operation based around dock boss Dave Monks is small fry; she has him under surveillance for 60 kilos of cocaine bound for the docks. Carter, working undercover, has to warn one of the thieves, Dave's son Pete. Accomplice Tom Harris agrees to give Meadows and Lacy evidence after he is arrested. For his help, Dave Monks agrees to give Carter more work. Green goes undercover in the Monk's club with Dave's daughter Chloe, but Meadows & Lacy spot Dave telling Pete to kill Chloe's boyfriend and business partner Asif Perreira. Pete bottles it and Asif goes into protective custody. Green blows her cover with Chloe to gain her trust, and takes her to Asif. Carter tips off Meadows about a bust, but Dave set it up as a decoy run. Meanwhile, Turner gets a clean bill of health after being stabbed with a hypodermic needle a few months earlier.

Part One- Demolition Girl: Whilst on cordon duty for a high rise demolition, Armstrong is approached by a woman, Sian McGuire, who claims her son is in the block. When it appears Sian was lying, after the search, she reveals her diary is inside detailing a rape at the hands of her uncle, Graham Boyce, when she was a child. Gold agrees to arrange a delay to the demolition, on the condition Sian makes a statement against Boyce. When the diary isn't found, the demolition goes ahead. As alarms ring, signalling the demolition, Sian runs at the block, chased by Armstrong. As the building collapses, the pair are nearly crushed to death. Sian, with the help of Moss, Masters and Armstrong, arranges a meeting with her aunt, Yvonne. However, the team are left with no choice but to arrest Boyce. Sian's diary is recovered from his shed, and he confesses. As Armstrong gets reprimanded by Gold for interfering with the interview, she goes to get drunk with Gayle, but her actions at the end of the evening lead to disaster. Meanwhile, Taylor and Stone look for a missing pedigree dog.

Part One- Before: Weston and Valentine attend a serious assault in which a drug dealer has been brutally assaulted and has jaw broken in a hammer attack. Weston tries to get the victim to talk, while Dasari looks for a suspect. A teenager is brought in, but he has to be bailed for his own safety, when it is revealed he is witness protection. After Dasari tears him apart in interview, he agrees to help her out. The fallout has disastrous consequences however, when he is found dead at the bottom of a tower block.

Part One: Brown and Ghir respond to an assault in a car park, with the victim none other than Banksy's wife Naomi Woods. The suspect, Bobby Henshaw, is after retribution, when Woods defended Alistair Finch, a driver who killed Bobby's brother Michael in an RTC a few months earlier. Banksy tries to get Bobby's parents to open up, but his mother Judy blames him for his Michael's death. His associate Gavin Wishart, points CID in the right direction. When Banksy goes home to speak to Naomi, he finds Bobby holding a knife to her throat.

Part One: The trial for Tom Norris starts, with the charges rape and murder, and Banksy's wife, Naomi Woods, is named as defence counsel. Fallon Thomas runs from Brown and Green when they go to pick her up, to bring her to court. Paula Merrick suffers a dose of nerves and is found out of her face on vodka, but Ryder cleans her up and brings her to court. She is torn apart on the stand, and is then found in the bathroom talking to fellow witness Sophie Oduya. Naomi witnesses the incident, and the judge throws it out for police orchestration of collusion between witnesses. Nixon issues a warning to Norris about witness intimidation, but a call comes in about an assault in the same alleyway where Paula Merrick was found, leaving Nixon horrified that Norris has restarted his crimes.

Part One: With Roberts, Taylor and Weston off sick, Heaton joins Gold on patrol. Stone, Valentine, Brown & Gayle attend a stabbing. The victim, Jake Quinn, claims his girlfriend Nicola's husband, Gerrard Parry, did the stabbing. When Stone and Brown go to his home, he makes a quick escape. Nicola claims Jake's obsessed with her, but there are more phone calls to Jake than from. When Parry is found, he denies the stabbing, and forensics prove Jake may have stabbed himself. At his work, Smithy and Gold find a gun holder in his locker, and he is seen leaving with Sophie Parry, Nicola and Gerrard's daughter. As Smithy and Gold go to Sophie's school, Jake is found waving a gun around.

Part One: Uniform start a search party for a missing eight-year-old, Bethany Riley. As a search party gets underway, Valentine is assigned as FLO. Ghir tragically finds her body a few miles from her school. Suspicion first falls on her father, who is significantly older than his wife, after a dodgy alibi. Suspicion then falls on football coach Ryan Kemble, whose van was seen nearby when Bethany vanished. When one of her blazers appears in his van, he is arrested. Camera footage shows that one of Bethany's fellow pupils has a fixation on her, but is he capable of murder?

Part One: Perkins goes on the 'big job' with cab boss Alan Brady. As they're parked up, Brady points a gun at a teenager and shoves her in a cab. Hajo Trautzschke and Ina Zimmermann of Leipzig PD arrive when it appears the victim, Charlotte Wenger, is a German national. Trautzschke‘s brute tactics annoy Meadows, especially when he manhandles Perkins in a raid on Thompson & Ray. Jimmy Thompson has already taken Charlotte away, so Perkins meets him in Piccadilly Circus. Both Charlotte and Jimmy run off; Jimmy is arrested by SO19, but Perkins and Charlotte go missing, kidnapped by the ringleader. He reveals his name as Viktor Hauptmann, and he is meeting a computer hacker, Hans Muller, at London City Airport. Trautzschke arranges for an undercover cop, Jan Maybach, to swap with Muller. As soon as Perkins leaves with Jan, the gang get on a plane bound for Germany.

Part One: Masters is on scene when a pub landlord discovers the body of a prostitute, Kelly Porterfield. Her ex-boyfriend Andy Donnelly is a suspect for Kelly's fatal overdose. His girlfriend, Jen Kilshaw, is obviously underage, so Masters focuses on getting her away from Andy. Masters promises Kelly's mum that she will bring down who is responsible. Walker, Heaton and Masters look at two overdoses, including Kelly's, and a chain of locations where the girls came from and ended up, and fear that a sex trade operation is spreading across the UK, and Andy appears to not be the main suspect in Kelly's murder or the smuggling operation.

Part One: Moss sets up an OBBO on Rob Towler, but when nothing happens overnight, Turner suggests she goes back under. Moss’ SO10 handler, DS Jim Rutherford, comes to Sun Hill to help with the case. When sees his partner Gordon McArdle at Rob's before a deal, and fears he is being set up. She voices this to an uninterested Turner, and has to intervene herself.

Part Two: With a gang member and SO19 officer down, Moss and Rob Towler speed off on a bike, chased by the gang. Gayle and Ghir call in to say they lost both targets, before Turner receives a cryptic call from Moss but is quickly cut off. She confronts Turner at her storage unit, after failing to find her passport at home. After putting a gun on him, Turner is grounded. When he finds Towler and Stevie at Towler's father's home, Towler’s father is shot. When Moss and Towler flee, Turner finds himself suspended.