When Thomas sides against her findings on a controversial case, Nikki suspects foul play.
Nikki is humiliated in court when a barrister accuses her of making a serious error.
The team's search for the killer uncovers links to the Troubles in Northern Ireland.
A shocking incident on a suburban street brings back painful memories for Jack.
The team must unearth the connections between a diverse range of suspects.
The Lyell team are summoned to a waste dump in Brighton where a body part has been found.
A head teacher takes drastic action against local dealers.
As new drugs hit the streets, Nikki, Jack, Clarissa and Thomas deal with the consequences.
A mistake has been made, and Thomas is targeted as a scapegoat.
Nikki and the Lyell unit are called in to investigate an attack against a transgender man.