PCs Valentine, Roberts and Taylor attend the reported abduction of a baby girl left in the charge of her nanny. DI Nixon leads the subsequent investigation, and PC Stamp takes on the role of Family Liason Officer.
DI Nixon, preparing to leave Sun Hill for a new job with the Child Exploitation Unit, leads an investigation into the importation of drugs. When the team moves in on the gang, all they find is a consignment of pineapples. However, the case soon warms up with their informant getting kneecapped and the kidnapping of the main suspect's daughter.
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, for the victim hitting on 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. With the case falling apart, the case takes a sinister twist when the E1 is found alight.
CID investigate the arson on the E1 bar. Stone, Smithy and Max 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.
Smithy and Gayle see a driver abandon a lorry containing illegal Afghani immigrants. In an attempt to win the trust of a suspicious community, Smith visits a refugee centre, but a riot breaks out on the local estate.
Smithy is told by Stone he shouldn't confess to his assault on Jason Devlin, as he'll go down for the assault on Stevie. Stevie tells Will that Devlin has a suspicious bag in his car boot, which is full of stolen jewellery. Devlin originally says he is unsure of his attacker, until he is arrested for assaulting Stevie and possession of stolen goods, where he changes his evidence and accuses Smithy of planting. Smithy uses Ara Byat to get her boyfriend, a Devlin associate, out of fear, to testify against them.
Weston leads her team on a public order training exercise after the disastrous riot where Roger was snatched & Stevie was assaulted. Smithy and Stone clash over recent events. Meadows and Manson deal with the allegations against Smithy. Heaton reveals that he is to leave Sun Hill to lead a specialist unit dealing with human trafficking. A witness to Smithy's attack on Devlin comes forward.
When Jala Byat goes missing, the team are sidetracked and have to go out on a limb to make sure justice is done for the Byats in the trial, when key witness, Ara Byat's boyfriend refuses to give evidence until she is found. Weston tells Heaton she'll give him a year at his new division, and Kezia and Stuart transfer over.
Sergeant Stone and P.C. Ben Gayle are out on patrol when they discover teenager Danny Sissoulu has been beaten unconscious, while his distraught younger brother, Kip and friend Mo Campbell are covered in blood.
An 8-year old boy is abducted from his school, and his mother automatically points officers to his father - her ex-husband. When they find him, he explains both are in the middle of a nasty custody battle, and he hasn't been allowed near his son in 3 months. Suspicion falls on the mother, the father or the mothers new partner, but are they telling the truth?