In prison, Muslim extremist and cleric Zubeir al-Saad has been radicalising men, preparing them for suicide missions in the UK.

MI5’s mole Ashur is helping Erin and Dimitri in uncovering an imminent plot. Arming him with a bug, they send him undercover to unearth what is being prepared. Mani – a key player in the attack – and Anthony, their ‘handler’, need to be tracked if MI5 has any hope of foiling the terror plot.

Erin and Dimitri have promised that in exchange for helping them, they will ensure that his daughter has a safe passage to the UK. But something goes disastrously wrong, and Anthony – suspicious that an MI5 mole is among his men – shows Ashur that he, in fact, has her hostage. He says that the only way she will be safe is if both Mani and Ashur carry out the plot.

Ashur turns against MI5 and those who have said they will help him. Finding out his daughter’s life is in jeopardy has made him distrustful of the agents, and so he destroys the bug and so cutting all communication with MI5. Knowing an attack is set to happen in hours or even minutes, it’s all hands on deck at MI5 HQ.

Meanwhile, in Trafalgar Square, Ashur has strapped himself to a bomb. Erin manages to make it just in time, and they think they’ve stopped him. But Ashur shows Erin footage of her daughter who’s been taken hostage by Anthony. She’s told that if MI5 prevent the attack, her daughter will be killed. Luckily, Dimitri saves Erin’s daughter, but it makes her question her job.

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