In the winter of 1617, the sea around the remote Norwegian island of Vardø was thrown into a reckless storm. The men of the island, out fishing, perished in an instant and Vardø became a place of women. Eighteen months later, a sinister figure arrives. Summoned from Scotland to take control of a place at the edge of the civilized world, Absalom Vardø as a place flooded with a terrible evil that he must root out at all costs. History Hit's Alice Roberts speaks to Kiran Millwood Hargrave about her novel, The Mercies, a story about how suspicion can twist its way through a community.