Amy needs to help Kirsten after the passing of someone on the hub. She is faced with a ticking clock to clear Kirsten's name before she is made into a scapegoat.
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.