In 2012, in a Middle Eastern souk, CIA agent Miles Brookhaven was attacked. He was infiltrating rebel groups in the area and no one was certain if his cover had been blown of if the act was just a arbitrary attack. Now, Liz Carlyle and her new Counter Terrorism unit in MI5 have been charged with the task of watching the international under-the-counter arms trade and British Intelligence forces have become increasingly concerned that extremist Al-Qaeda jihadis are building their power base ready to launch another attack. As the pressure mounts, Liz and her team must intercept illegal weapons before they get into the wrong hands.