Nikki and the Lyell unit are called in to investigate an attack against a transgender man.

A mistake has been made during the course of the investigation, and Thomas is targeted as a scapegoat. As frustration grows between the Lyell and the acting DCI, can Thomas rally the team to gather crucial evidence to find the killer before they strike again?

With new drugs hitting the streets, a head teacher confronts the dealers preying on his community, as the team deal with a surge in drug-related crime.

When tragedy strikes close to home, it puts head teacher Noah Taylor on a collision course with the criminals responsible. Can the Lyell team help him stop the cycle of violence?

The Lyell team are summoned to a waste dump in Brighton where a body part has been found. The search is on to recover the other remains.

The team must painstakingly piece together the evidence and unearth the connections between a diverse range of suspects.

A shocking incident on a suburban street brings back painful memories for Jack, forcing him to revisit his past.

During the team's search for the killer, Jack works alongside an old friend from Northern Ireland, and they uncover a complex conflict.

Nikki is humiliated in court when a barrister accuses her of making a serious error in the case of a policeman who may or may not have been murdered. Meanwhile the team investigates the death of a medical researcher found in a canal with mysterious puncture marks on his body.

When Thomas sides against her findings on a controversial case, Nikki suspects foul play and takes steps to prove her theory. Jack and Clarissa follow a forensic trail connecting a dead researcher with a billionaire scientist and a secret testing programme.