The Mercies, Kiran Millwood Hargrave, Picador, £14.99

To the people of the island of Vardo, just off the north-west coast of Norway, Christmas Eve 1617 brings with it an awful calamity.

A sudden storm descends on their fishing boats, wiping out almost the entire male population. At another time, in another place, this could have been the basis for a novel about how the island’s women triumph against adversity by taking on their menfolk’s roles and proving they could do them just as well. To be fair, there’s a contingent of Vardo women who are game for doing just that, led by the formidable Kristen, a natural community organiser, who leads boats out to fish in defiance of the rules of propriety.

Unluckily for them, this is a time when the newly installed Lensmann of Finnmark, Scotsman John Cunningham, has summoned his compatriot Absalom Cornet to act as commissioner, living in the town and enforcing Christian values. Cornet came to Cunningham’s attention through his successful prosecution of a witch in Orkney, and his brief is chillingly simple: “We are to root the Church more fully into the land there. And destroy its enemies.” Those “enemies” are principally the native Sami people, who still practise their traditional ways, making them, in the eyes of the Church, witches.

Hargrave tells the tragic, terrible story through two main characters: Ursa, a shipowner’s daughter from Bergen whom Cornet selects as a suitable bride on his way to Vardo; and Maren, an islander who lost her father, brother and fiancé in the storm and remains loyal to her Sami sister-in-law Diinna, however much her adherence to the old rituals might offend Vardo’s pious church-goers.

Diinna understands as well as anyone the futility of resisting the men bent on purging all traces of Sami mysticism from this community of Christian women: “We are as men to the sea, caught on their currents.”

In this climate of persecution and dread, Maren and Ursa fall in love, though it takes them a while to realise it, and their love story is the core around which The Mercies is structured.

Character is one of Hargrave’s strengths, and one of the novel’s most satisfying aspects is watching Maren and Ursa develop as the situation around them grows ever more dire and threatening. From naïve, flighty teenager excited by the prospect of being married to a commissioner, Ursula is brought rudely down to earth by the harshness of life on Vardo, and increasingly repelled by her husband as his cold, ruthless nature is revealed.

Maren’s evolution is no less painful, as her loyalty to Diinna, Kristen and her new friend Ursa drives a wedge between her and the people she’s grown up with, not least her own mother.

Passionate, stirring and conveying a terrifying atmosphere of claustrophobic oppression, Hargrave’s gripping tale of courageous women facing overwhelming odds is helped along no end by the vividness of her bleak island location and her depiction of the dynamics of a God-fearing fishing village as opposing factions struggle for control.