DS De Costa is questioned about the incident involving Margaret Barnes on the stairs, Samantha Nixon and Gary Best investigate the suspected date rape of a young girl and Gina Gold struggles to juggle the pressures of work with her cancer treatment.
Inspector Gold goes out on patrol to keep rumours at bay regarding her absences from the station. MIT's case against Scott Burnett hits a major hiccup over the leaking of evidence, and DC Jo Masters' murder case begins to unravel when her witness is intimidated.
Tensions run high when Greg Campbell is intent on stopping murder suspect Scott Burnett from marrying PC Honey Harman. Conflicts arise between an ambitious soccer coach and the father of one of the team who has a Premiership trial scheduled for the following day. The family of one of the Sun Hill team is involved in a serious car accident.
Sun Hill officially reopens after the fire. DCI Meadows appoints Gina Gold as FLO to Supt Okaro in the aftermath during the investigation of his wife's accident. DC Sim is assigned to the case of a recently released sex offender, but discovers there is far more to the case than previously suspected. DC Perkins continues to help DS De Costa with her apparent stalker. DS Hunter continues to be attentive to DS Dixon.
Supt Okaro confronts the driver of the car involved in the accident with his wife. DC Sim has difficulty reconciling the suicide of her child abuse witness, but continues to investigate the case in an effort to save the victim's sister from a similar experience. DS De Costa confronts Margaret Barnes about her obsessive attention, with unexpected repercussions. A counterfeit DVD case turns domestic.
Margaret Barnes' obsession with DS Ramini De Costa continues to escalate, and when Margaret's employer takes action to have her transferred, it pushes her over the edge with serious consequences for DC Perkins who has been trying to support Ramini through the ordeal. DC Masters, Acting DC Best, PC Powell and PCSO Bryant work on a drugs case while PC Stamp and PC Casper investigate a series of graffiti incidents with a difference.
DS Ramani De Costa and PC Valentine race against time to discover who and where Margaret Barnes' stabbing victim is. Meanwhile, DC Perkins lies bleeding on Rimini's bathroom floor. DS Hunter and DS Nixon investigate a curious case of lewd photos. DC Masters' drugs case leads PC Powell and PCSO Bryant to make a surprising connection.
After his family's funeral, Supt Okaro and Gina Gold reflect upon their lives, and Gina tells him of her illness. "Operation Mercury" continues to investigate the network of suspects involved in the supply of drugs to the Cole Lane Estate. DSs Samantha Nixon and Phil Hunter investigate a stolen laptop - leading to complications for the owner, meanwhile, another chapter of Phil's life catches up on him.
More drug raids reveal no hard evidence to incriminate Lewis McKenzie, but only more of his children and their mothers. DCI Meadows puts pressure on one of the mothers, Letitia Watson, to expose Lewis' dealings. DS Nixon and DS Hunter fall out over his handling of Kate Maltby's pregnancy. PC Lance Powell is held at gunpoint and the real identity of his "nemesis", Adi Mateen, is revealed. Sept Okaro returns to work. PCs Murphy and Kent investigate a harassment incident against a lady-friend of his.