When Raza is arrested, Gabe and his partner Holly identify him as a potential informant for London's Counter Terrorism Special Unit.
Gabe pushes Raza to get close to Dadir, the brother of CTSU's murdered informant and the only lead to identifying Big Shot.
The toll of Raza's double life begins to weigh heavily on him, but he finds a crucial new lead. Gabe runs into a ghost from his past.
CTSU mount a surveillance operation with Raza at its heart. Gabe visits a contact from his undercover days. Dadir drags Raza deeper into danger.
Holly's curiosity reveals the uncomfortable truth about Gabe's undercover past, and her probing unwittingly leads to his two worlds colliding.
The terrorist cell is exposed and the final tragic details surrounding the attack on Cafe 66 are revealed.
Paddy Considine
Gabe Waters
Bel Powley
Holly Morten
Nabhaan Rizwan
Raza Shar
Arsher Ali
Imran Aziz
Sharon D Clarke
Rose Asante