DS Ronnie Brooks and DS Matt Devlin are assigned to investigate the death of a dead nine-month-old child who was found inside the sports bag in the parking lot of the hospital. The first obvious suspect is child's mother, Dionne Farrah (Venetia Campbell), but they learn that she had left the child at home by himself pending the arrival of the babysitter as she was concerned that she would be fired if she was late to work. The sitter was refused entry to the building and the boy was poisoned by carbon monoxide poisoning due to a faulty central heating system from the gas heater in his flat. A fellow tenant, Mike Turner (Tony Maudsley), had been bribed by the landlady, Maureen Walters (Lorraine Ashbourne), to harass the occupants into leaving so that she can renovate the building for more profitable developers as means for getting higher rent and he is charged with tampering with the heater as means of getting rid of tenants who refused to vacate their homes, and in the process killed the child. However, the case is declared a mistrial when it is claimed that the testimony of the building's French caretaker was wrongly translated. However, the trial gets back on track when the team finds that Mrs. Walters has also been bribing environmental health officers, and Steel persuades Turner to testify against her. Steel tries to prosecute Walters for gross negligence and corruption of public officials.

When a treasure hunter with a metal detector uncovers a nine-year-old skeleton in a shallow grave aside the Thames mudflats, it forces Brooks and Devlin to reopen a contentious murder case when they identify the remains as those of David Ackroyd who disappeared in 1999. His supposed killer and business partner, Luke Slade (Iain Glen), was eventually convicted of murder although no corpse was found and an unreliable witness claimed that Slade told him he had slit his victim's throat but the medical examiner finds that he was shot in the head. As a result, it would appear that Slade is the victim of a miscarriage of justice. Steel, however, is far from convinced and, when Slade represents himself in court, it becomes less about the trial and more about the vendetta between the two men. Slade soon files a writ to have his conviction overturned and the Crown prosecutors learn that Slade will represent himself at the appeal. Whilst in jail Slade has become skilled in the law and wins himself a re-trial, putting James Steel's career on the line in the process as was the original trial prosecutor as this was his first case with the Crown Prosecution Service. Steel and the police have to build an entirely new case against him and Steel soon finds himself before his own hearing alleging misconduct in his pursuit of Slade but fortunately for Steel, a visit to Slade's old cell-mate yields results.

• Original episode and this adaptation inspired by the Billionaire Boys Club case.

When remains of a small boy are uncovered in a wall by a construction crew, the Police are called in. The remains are later identified as Thomas "Tommy" Keegan, who disappeared in 1983 at the age of eight, so his body was found 25 years after he was reported missing. The boy had his skull crushed with a blunt object and his body was bricked into a wall. Brooks and Devlin meet with the retired policeman in charge of the original investigation and he was convinced that he knew the culprit, Edward Connor (Anthony Higgins) a neighbour and a suspected paedophile, who was arrested but the police couldn't get - or beat - a confession out of him so he was released for lack of evidence. They also meet Julia Mortimer (Holly Aird), a childhood friend of Tommy, who used to play with him when they were younger. She tells the police that she had seen Tommy the day before he died but they notice an anomaly in her statement and ask her to undergo EMDR therapy, also known as regression hypnosis, to see if they can retrieve any additional memories as they believe that is subconsciously suppressing her memories of the events of the time. Julia names her estranged father Vernon (Keith Barron) not only as the killer but as a paedophile himself who molested her too. This leads to a history of sexual abuse and abuse of trust and it's left up to Steel to get the man to admit it on the witness stand but the court trial leads to angry exchanges between Julia and her father. However, Steel soon finds that his whole case rests on a very upset and potentially unreliable witness.

• Original episode and this adaptation inspired by the George Franklin case.

When an arson attack on a Turkish club claims kills 17 people, all undocumented illegal immigrants, Brooks and Devlin are under pressure to discover just who was behind it. Using CCTV, they manage to trace a suspect to a nearby hospital and what was first thought of as a racist attack soon turns out to be a lot more complicated. The perpetrator, Nazim Kazaba (Nabil Elouahabi), is caught as part of the device he used went off in the blast and something embedded in his leg but is refusing treatment, the situation is not helped when a suspect's human rights gets in the way of obtaining the crucial evidence. Steel's attempt to force the man to undergo treatment is unsuccessful so the police just wait for the wound to fester and, with evidence finally in hand, charge him with murder. The defendant decides to cut a deal and his information leads them to Ediz Kilic (Ken Bones), one of the most prominent members of London's Turkish community who is also a people smuggler who Kazaba claims forced him to silence the clubbers, who were ready to expose his activities. The prosecutors struggle to build a case as a conflict emerges between justice, community relations and racial harmony. Steel jeopardises his friendship with a Turkish school mate, who resents being under suspicion, from his student days to get information to bring Kilic down.

• Original episode and this adaptation inspired by the Happy Land fire caused by Julio Gonzalez.