After Amy and Kirsten battle for their lives against an armed hugger, Amy follows a new lead to the Middle East. She discovers someone on the airbase was complicit in the attack.
The mysterious disappearance of a Scottish fishing trawler and a passing on-board a Trident nuclear submarine bring the police into conflict with the Navy and British security services. DCI Amy Silva leads an investigation on land and at sea into a conspiracy that threatens the very heart of Britain's nuclear deterrent.