Action-packed drama taking us into the thrilling world of MI5, the clandestine security service, and the people who make up the elite team. There's organized crime, terrorist activities, embassy sieges, weapons proliferation, subversives, anarchists and drug traffickers, not to mention the conflicts and power struggles that they have to deal with back in the office. A topical and edgy drama about passion, jeopardy and the intrigue of people who have to lie for a living - and who can never tell the truth to their loved ones about what it is that they do.