Explosives Officers Lana Washington and Joel Nutkins are called out to investigate a potential bomb factory in a London housing estate, but there's no sign of the bomb makers.

London is still reeling from the events at Westhaven; Lana Washington must solve the mystery of who is behind the terrifying attacks.

Far-right group the Crusaders claim responsibility for the mosque attack; Lana finds a forensic link between the bomb at the mosque and the one at Westhaven, and they might have been bombed by the same person.

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; Sonya manages to trace the chemical explosive HMX used by the bombers to Porton Down.

Lana struggles to come to terms with her personal loss, and her failure to prevent the explosion; counter terrorism officers identify the bomber and launch a massive manhunt.

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.