Prison transport officer Amber (Izuka Hoyle) is thrown into an explosive situation, when her formidable prisoner, Tibor (Tahar Rahim), is hunted by his crime syndicate, who are determined to stop him from testifying against them.

Amber and Tibor try to escape their captors, but when Amber's family's safety is threatened, she must confront her moral beliefs as Tibor pushes her to do whatever it takes to survive.

Desperate to reach Olly and baby Mia, Amber adopts Tibor's tactics, exploiting his weakened state. Her transport team are drawn into Tebbit's investigation to expose Pegasus' plan as Declan closes in.

As Amber reunites with her family and Tibor confronts his mother, buried secrets bring unexpected understanding. But a single misstep thrusts them into their most dangerous battle yet.

With her family in danger, Amber and Tibor hunt down O'Neill as Tebbit uncovers the crime syndicate's deadly plan. Desperate to find her baby, Amber seeks out her estranged, incarcerated mother for help.

In the gripping season finale, Amber and Tibor race through London to reach the Old Bailey as they are relentlessly pursued. Facing mounting threats, Tibor makes a devastating choice with far-reaching consequences.