The apparent suicide of a DJ leads Nikki to question her judgement on a strikingly similar case from her past. The similarities between the cases reveal that a copycat killer is out there. Meanwhile Tony, a family man recently released from prison for an attempted murder he supposedly did not commit, struggles to come to terms with his new life.

Nikki is arrested after a senior pathologist that she previously came to blows with is murdered.

A young British Muslim returns secretly to the UK. Although initially suspected of drug smuggling, concerns over her intentions soon escalate.

Thomas must put his personal feelings aside as the team track down Begovic before she and her extremist compatriots strike out again.

An ex-convict is killed and suspicion lands on a recently released child killer.

The team revisit a 15-year old case when they discover that Paul may have lied about his identity so far.

The accidental fatal shooting of a Polish teenager in an armed police operation triggers a series of murders that link Turkish gangsters, a grieving family and a fractured firearms unit.

Jack leads the hunt for suspected killer Bruno, the brother of the Polish teenager shot by the armed police, and enters London's small but devastating gun trade.

A family is coldly murdered during a picnic by the River Malt.

Amy’s past begins to catch up with her risking her medical career and everything else.