After three people are shot dead at a petrol station, Nikki and Jack attempt to catch the person responsible and stem a public crisis in London. DCI Jane De Freitas’s fall out with Chief Supt Robert Drake become the least of her worries.

DCI De Freitas’s expertise in victim and killer profiling is used to help narrow down the suspects as she contains her undercurrent of animosity with Drake.

Nikki and Jack are called in after a man is run down and killed by a tube train. When a female vicar is then murdered after being followed on the Underground, they need to build a case against her distraught husband.

After a young roofer is stalked and killed on his journey home, Nelson and the team manage to identify a suspect on the tube cameras who links the murders.

After suspected paedophile Dale Barge is discovered dead in a children’s playground, Nikki and Jack are called into investigate.

After Daniel Garvey is discovered dead in his car, Louise is concerned that he may have been killed by his 16-year-old stepson Kevin, who has just left care.

The nanny of a Russian oligarch ends up being murdered in a botched assassination attempt whilst a bloody shootout also leaves an unknown hitman dead. The team work with DI Sarah Parks to ascertain the identity of the dead would-be assassin.

A woman is discovered dead in Maksim Bazhanov’s apartment, and after her mother turns out to be a major player in London, pressure is put on DI Parks’s investigation.

After Sergeant Sam Honeywell is discovered beaten and shot in his burnt-out car in Essex, the police are furious in what is a hugely emotive and political case for them, and DCI Jim Sullivan is determined to track down Honeywell’s killer. After a local drug dealer and son of crime boss Dean Fallon seems to have his alibi sewn up, suspicion falls much closer to home.

When the body of local criminal Jason Simons is found, it reveals secrets that challenge his identity and the course of the case.