Peter Faber, an ordinary German soldier, and Katharina Spinell, a young Berlin woman, are joined in a marriage of convenience that gives him temporary leave from the Eastern Front and her a widow's pension should he die out there. During their honeymoon in the German capital, stilted exchanges quickly develop into unbridled passion — so much so that both newlyweds are stricken when the time comes for Peter to return to battle.

So begins Wicklow, Ireland-based writer Audrey Magee's deeply impressive debut novel. Her title, "The Undertaking," refers to the waiting game Katharina must endure, first months then years, but also the military campaign Peter is part of and which threatens to sunder them.

Magee alternates between the characters and their separate plights. Katharina's is one of longing, but as the war drags on she also finds herself distraught about her sick baby, mediating between her bickering parents and routinely ducking for cover during British air raids. Peter must withstand frostbite, lice, hunger and exhaustion. But then comes the ultimate ordeal: Stalingrad. Initial jubilation — the prospect of victory within weeks and the glorious Third Reich stretching from the Atlantic to the Volga — is swiftly stamped out and replaced by the brutal reality that he and his men are mere "Cannon fodder. That's all. For Russian guns and German ambition."

A common structural problem for a novel comprising two perspectives is that one tends to be more absorbing than the other. Not so here. Magee skillfully distributes equal weight, meaning equal pathos and intensity. At war, we follow Peter's unit in a sequence of taut and exciting scenes, wondering who will be the next man to fall. At home, we watch as Katharina is paired up with a potential new husband, even though she has received no confirmation that she has lost the first. Magee also crafts some clever juxtapositions: While Peter eats stale gray bread, donkey soup or nothing at all, Katharina is spoiled by Dr. Weinart, a high-level Nazi, whose lavish dinner parties and luxury cakes made by the Führer's own baker are a bid to sweeten the taste of her brother's sacrifice and her husband's disappearance.

The couple's letters of love go some way to alleviating Magee's depictions of war. However, there is scant comfort to be found here. Magee adds layer upon layer of moral complexity. Do we cheer on Allied planes "mowing the earth, cutting down men," creating "a fresh crop of death"? More troubling is when her heroes act as villains. Peter's unit rapes and murders civilians. He rounds up Jews, striking terrified children with the butt of his gun; his wife and her parents move into a house owned by deported Jews and plunder their belongings — although not before disinfecting them.

Magee gives us an uneasy read, but it is hard to pull away. This is a devastating but quite stunning first novel.

Malcolm Forbes has written for the Times Literary Supplement, the Economist and the Daily Beast. He lives in Edinburgh.