When a crew member is found dead aboard the Trident nuclear submarine HMS Vigil, Detective Amy Silva is flown out to investigate.
With Vigil in danger, Amy must fight to continue her investigation. Meanwhile, Kirsten’s enquiries lead to tragedy.
Kirsten’s investigation takes her into the heart of Scottish politics, but when she unearths a navy cover-up, it leaves Amy questioning who she can trust on Vigil.
Kirsten closes in on the killer, but their capture reveals the grave threat that Vigil faces. On the submarine, Amy makes a terrifying discovery.
Vigil is forced into lockdown as disaster strikes. With hostile boats tracking the submarine and communications down, Vigil’s crew have to navigate this crisis alone. Kirsten desperately hunts for clues to reveal the source of the threat to Vigil, but with no word from the boat, she fears for Amy’s safety. Amy’s quest to uncover the truth places her in grave danger.
Amy is trapped and running out of time, but will assistance arrive too late? On land, Kirsten chases down the traitor’s accomplice. When the traitor on Vigil puts their plans into action, the crew are forced to fight for their lives.
When a weapons test turns deadly, with allies from the Middle East among the dead, all eyes are on DCI Amy Silva, who tries to ignore the politics to get to the truth.
After Amy and Kirsten battle for their lives against an armed killer, Amy follows a new lead to the Middle East. She discovers someone on the airbase was complicit in the attack.
When an officer is stabbed on base, Eliza warns Amy to get control of her investigation. Meanwhile, Kirsten uncovers key evidence linking a squadron member to the attack.
Amy and Eliza are held hostage by the dissidents at the heart of the investigation, who demand their help to infiltrate the base. Kirsten will do anything to find Amy.
In the aftermath of a brutal rescue mission, Amy is questioning everything. Kirsten begs her to come home, but Amy can’t let go of her suspicions.
Amy finally discovers the full scale of the conspiracy, and she must decide if she is prepared to risk everything to find those responsible.
DCI Silva and DI Longacre investigate the murder of a British citizen in the Arctic, but they soon find themselves caught in an escalating political situation.
Amy is on the clock to save a hostage, while Kirsten navigates international agendas in the Arctic in the hunt for a missing Chinese scientist.
Amy needs to help Kirsten after the death of someone on the hub. She is faced with a ticking clock to clear Kirsten’s name before she is made into a scapegoat.
Henrik and Kirsten close in on the missing Jia, with Amy not far behind. But as tensions rise and new allegiances are formed, the danger of the Arctic wilderness becomes apparent.
