After Kay tails Celia Herrington’s mystery visitor to a Ministry of Defence building, Dom is convinced that Kirsty will no longer be able to ignore their pleas for help. But first, they must hide Clinton’s dossier somewhere safer - after an attempted raid on Dom’s parents’ house.

Posing as volunteers, Dom and Kay visit Riverford Residential Home, suspecting it could be a front for the Brightmarsh Gang.

Dom and Kay, two ordinary PCSOs, are recruited by Detective Inspector Clinton Blair to go undercover and infiltrate the infamous Brightmarsh Gang.

Dom and Kay have a body to bury. They’re in a mess, frightened and completely on their own. Who else knows about their mission, other than Clinton Then, they bump into fellow PCSO Pricey in a 24-hour café, who doesn’t quite believe Dom and Kay’s story as to why they are caked in mud.

Dom ropes in Kay to help her gather evidence about Steve, and the pair trace him to a mysterious lock-up. Tevin piles on the pressure, and Kay gives Dom an ultimatum.

After being dismissed from MI5, Dom and Kay go their separate ways – but will new clues about a possible threat to the Notting Hill Carnival pull them back together?

Dom and Kay try to ambush Steve by breaking into his flat, but plans go awry. Kay’s loyalty is pushed to breaking point.

Dom and Kay start new roles at MI5, but each of them struggles to find their place. Dom takes a big gamble to impress a senior agent, sparking a dangerous chain of events.