The police launch an investigation to find the bombers, whose skill and sophistication keeps them one step ahead. Under pressure to get results, Helen makes a breakthrough.

Alex contacts the police with critical information about a new attack planned for that day, but Commander Francis warns the team against placing too much trust in him.

The EXPO team are stretched to breaking point dealing with a complicated device planted at the Campaign HQ of the Progressive Alliance. Lana tells Karl she wants to break up.

Expo Lana Washington is giving a routine talk, having just returned from secondment, when an explosion rocks the heart of the city. But is she ready to return to active duty?

As the team mourns Thom's death, a new lead emerges - an informant, promising intelligence on the terror cell. Meanwhile a journalist is sent a suspicious package.

Lana breaks protocol to try to help Alex, knowing he has nobody else to turn to. Then the team makes a shock discovery about the terror cell they’re tracking down.

Lana is faced with an impossible decision when she is kidnapped by the terror cell. A choice between her duty and saving those who matter the most to her.

As the bombing campaign intensifies, so do inter-community tensions as the far-right group English Flag take to the streets to blame Islamists for the attack.

Lana struggles to come to terms with her personal loss, and her failure to prevent the explosion. Meanwhile, Counter Terrorism officers identify the bomber and launch a massive manhunt.

Following the murder of a Counter Terrorism officer, Lana Washington and the EXPO team race against time to stop the bombers before they strike again.

Bomb disposal officers Lana Washington and Joel Nutkins are called out to a Met counter-terrorism operation at a London housing estate to investigate a potential bomb factory and suspected bomb-maker Andy Phelan.

A far-right group called the Crusaders claim responsibility for the mosque attack. Lana finds a forensic link between the bomb at the mosque and the one at Westhaven - were they both bombed by the same person?