An untraceable cargo. An unknown target. The international arms trade is about to become a national problem. In 2012, in a Middle Eastern souk, CIA agent Miles Brookhaven was attacked. At the time he was infiltrating rebel groups in the area. No one was certain if his cover had been blown or if the act was just an arbitrary attack on Westerners. Months later, the incident remains a mystery. Now, Liz Carlyle and her Counter Terrorism unit in MI5 have been charged with the task of watching the international under-the-counter arms trade.