The Aftermath, By Rhidian Brook

In the 1990s I viewed the shattered bells of Lübeck's Marienkirche, left where they fell after Allied bombing on Palm Sunday 1942, and accompanied by a cross of nails from Coventry Cathedral.

Reading Rhidian Brook's profoundly moving novel of postwar Hamburg, which briefly visits these bells, reminded me of the elderly German who taxed me in the Marienkirche with Allied atrocities in the firebombing of Lübeck, Hamburg and Dresden. A painful and intricate conversation concluded with a handshake and two linguistic gaffes on my part. I said the equivalent of "Glad to have stricken you," and attempted to retrieve this with "Stricken to have met you".

Brook's post-apocalyptic story is set in the winter of 1946 in the charnel ruins of Hamburg, where occupying British forces attempt to sift and organise a destitute German population: it is the era of denazification and non-fraternisation. The Aftermath is a narrative not only of both sides' barbarities but also of dire misunderstanding and complacency on the part of the occupiers.

Brook's beautifully written novel ponders issues of decency, guilt and forgiveness, in a world fouled with "the oedemic stench of the dying". The aspirations of a nation that murdered its way across the globe in quest of Lebensraum have shrunk to competition for shelter, food and cigarettes, the sole black-market currency.

"You must keep clear of Germans. You must not walk with them, or shake hands or visit their homes," ran the British non-fraternisation booklet. Brook's grandfather thought differently and shared his requisitioned property with a German family for five years. This was the seed of The Aftermath.

When Colonel Lewis Morgan, taking over the Luberts' opulent Modernist mansion, tells the German architect, "I'd like to propose a different arrangement," he flouts the code in the name of human decency – and unleashes upon both families a chain of mistakes. For his Welsh wife, Rachael, mourning a child killed by German bombs, no imaginable house could have "room for a German". Lewis is subtly drawn, a man whose fair-mindedness, combined with a failure of attentiveness towards his wife, paradoxically leads his family into a danger zone.

Brook's narrative perspective travels between characters: its uneasy compassion carries the reader across "clear lines of demarcation". We are forbidden to take sides. A macaronic feel characterises the juxtaposition of the occupiers' pidgin-German with the uncertain English of the conquered. A tribe of feral orphans scavenges in Hamburg's ruins. "Fuck your arse, Captain!" the urchins bawl, exercising English gleaned from the Tommies.

Mother-loss overarches the action like the Marienkirche's great arch transept: in Frau Lubert's absence, in Rachael's paralysed heart – and, harrowingly, in the mummified corpse of the orphans' mother: Bombenbrandschrumpffleisch – body-shrunk-by-fire. Edmund's involvement with the ferals, shadowing his father's policy of fairness, is nearly fatal. Brook's characters share a common embroilment in a viscous moral medium: the results of good intentions may be confounding.

The meticulous integrity of Brook's prose style builds a narrative of chastened humans, ending less in tragedy than in a kind of redemptive inertia - turning back from the brink, taking time to mourn.