In the frigid waters off the Arctic Ocean, north of Greenland, the anti-whaling ship, The Sentinel, and her crew face off against a harpoon ship in search of Humpback whales. When the two ships collide and a suspicious explosion sends both ships to the bottom, the crews take refuge on what they think is a peninsula attached to the mainland, but is actually an island, recently freed from a glacial ice bridge. Seeking shelter, the two opposing crews scour the island for resources. Instead, they find Viking artifacts, the preserved remains of an ancient structure and a stone totem warning of horrible creatures buried in the island's caves. Facing violent, frigid storms, a hungry polar bear and the very real possibility that they are stranded without hope of rescue, Jane Harper leads the two crews, who must work together to defend themselves against an ancient evil upon which the modern stories of both zombies and vampires are based. The original undead are awake and hungry. Beware the Draugar.

A battle to the death with six-hundred-year-old zombie Vikings in the frozen far North was just the beginning… Undercover activist Jane Harper and father-and-son whalers Jakob and Willem Olavson thought they sent the walking corpses to their graves for good, but the intelligent parasites controlling the dead flesh lived on to keep fighting―and infecting. Now Jane’s Nordic allies and a motley crew of mates are shoving off on a new monster-killing ship to take the battle to the insidious creatures before they take over the world. This time, though, they’re up against more than just a handful of ancient zombies on an isolated island. Even if Jane and her crew can conquer an army of the swimming dead―murderous and cunning zombie whales―they’ll still face a floating graveyard of ghost ships packed stem to stern with the next wave of the ravenous undead…who are hungry to settle the score with the last hope of humankind.