Enlisting in the First World War I puts Canadian recruit Angus MacGrath in a quandary he could never have imagined.

He's from Snag Harbour, a small coastal town in Nova Scotia, and has spent most of his life around boats. He has a flair for art too, which his father has always dismissed compared to the real man's work of sailing trading vessels along the coast.

When his wife's brother Ebbin goes missing in action in France, Angus joins up in the hope of somehow tracking him down, although this is a slap in the face to his father's strongly-held pacifist views. Because of his artistic skills, Angus is assured he'll be working behind the lines as a cartographer (he reasons he can scour military hospitals in London for Ebbin), but on arrival is actually shipped out to the front line. Once in France, he makes a discovery that sends his loyalties to his family, his brother-in-law, the army and the truth on a collision course with each other.

The setting for this human drama is an exceptionally well-realised depiction of life in the trenches in all its horror, confusion, exhaustion, grime and inescapable dampness. Duffy does an excellent job of summoning up this quagmire where, at any moment, one's closest comrade could be snatched away by a sniper's bullet. She gives as much attention to gritty, mundane details like men lighting matches to burn nits' eggs off their clothing as she does to the unique brand of fear that arises from becoming disorientated and lost on sorties across no man's land.

This arresting portrait of men in combat is, however, interspersed with cutaways to Snag Harbour, where Angus's son, Simon Peter, is coping with a father at war, an uncle presumed dead and a grandfather whose rage and despair at the war seems to be driving him out of his mind. If this novel is about anything it's about the relationship between Angus and his son, but Duffy's wartime scenes are almost too accomplished. Angus's search for Ebbin, and the ethical position it puts him in, is such a strong storyline that the book feels a little unbalanced once it's curtailed. Although the real story she's telling is subtler and deeper, her bait and switch partially backfires as The Cartographer Of No Man's Land winds up feeling like a somewhat less compelling novel than it started out.