They were thankful he was dead. They were grateful when they discovered that he wasn't. Returning from Afghanistan, Youssef is obliged to work for MI5. Risking his life, he goes undercover to discover a plot that threatens the lives of millions of people. Forced to live on his wits, he fights people he once saw as allies. If he is discovered he will be killed without a second thought. London is threatened by the greatest act of terrorism it is possible to commit. Its fate rests in the hands of one young man. He risks everything to save the ones he loves - and the ones he hates.