When worlds collide

The huge ambition of Kamila Shamsie's fifth novel is announced in the prologue. As an unnamed captive is unshackled and stripped naked in readiness for the anonymity of an orange jumpsuit, he wonders: "How did it come to this?" The vastness of the question as applied to a prisoner in Guantánamo is a challenge to which this epic yet skilfully controlled novel rises in oblique and unexpected ways.

Unfolding in four sections, the novel traces the shared histories of two families, from the final days of the second world war in Japan, and India on the brink of partition in 1947, to Pakistan in the early 1980s, New York in the aftermath of 11 September and Afghanistan in the wake of the ensuing US bombing campaign. At its heart is the beautifully drawn Hiroko Tanaka, first seen in Nagasaki in August 1945 as a young schoolteacher turned munitions factory worker whose artist father is branded a traitor for his outbursts against the emperor and kamikaze militarism. She falls in love with a lanky, russet-haired idealist from Berlin, Konrad Weiss, with whom she shares - along with other key characters - a love of languages. But their romance is curtailed by the flash of light that renders Konrad a shadow on stone and burns the birds on Hiroko's kimono into her back, a fusion of "charred silk, seared flesh".

Hiroko finds refuge in Old Delhi, in the twilight of the raj, with her dead fiancé's sister Ilse and her English husband James Burton. Befriended by the unhappy Ilse, Hiroko is more drawn to Sajjad Ali Ashraf, a dashing Muslim employee who agrees to teach her Urdu. Her hosts discourage their romance ("His world is so alien to yours"), even misinterpreting a moment of tenderness as one of predation by Sajjad. Yet the couple grow closer as partition sunders Sajjad from Delhi as shockingly as Nagasaki was lost to Hiroko.

In Karachi, the saga of the Weiss-Burtons and Tanaka-Ashrafs shifts to Hiroko and Sajjad's son Raza, a linguist given to impersonating Afghan refugees from the Soviet invasion of 1979, and James and Ilse's son Henry, a Kipling-like figure mourning a lost Indian childhood (his daughter is named Kim). As Harry Burton, Henry has transferred his idealistic allegiance to his adoptive US, becoming a covert CIA operative in cold-war Pakistan. Raza's naive bid for a kind of gap year in Afghanistan's training camps with his Afghan friend Abdullah brings adventures with gunrunners and poppy growers, but also sobering loss for the family and enduring guilt for Raza.

After Hiroko decamps to New York, disgusted by nuclear posturing between India and Pakistan, and encounters Abdullah as a taxi driver, the final section alternates between an apartment she shares with Kim, overlooking the smouldering fires of Ground Zero, and Afghanistan, where Harry and his interpreter Raza have joined forces in a private security firm. CIA backing for the mujahideen's resistance war, and abandonment of them once the Soviet army withdrew, is seen as a grim policy failure whose legacy is being reaped in "Jihadi blowback". But pivotal to the novel's final betrayals, guilt and loss is a conversation fraught with suspicion and misunderstanding between Kim and Abdullah. As Abdullah says in exasperation, "everyone just wants to tell you what they know about Islam, how they know so much more than you do, what do you know, you've just been a Muslim all your life".

Through its succession of seemingly disparate, acutely observed worlds, Burnt Shadows reveals the impact of shared histories, hinting at larger tragedies through individual loss. The two families, while watching each other's back, can also prove instrumental in each other's destruction. There are minor flaws in plotting, and occasional excesses - gorilla suits as modes of escape, or soft toys sentimentalised as road kill to make a point. But the subtlety lies in repeated patterns of allegiance and estrangement, betrayal and atonement, in the echoes between kamikaze pilots and suicide bombers, or between Ilse's alacrity in branding Sajjad as a rapist in the novel's Forsterian vignette and Kim's suspicion of Muslims after 9/11.

The final section's title, "The Speed Necessary to Replace Loss", is taken from The English Patient, a guiding spirit, though this novel begins where Michael Ondaatje's ends, with a mushroom cloud over Asia. Anita Desai's influence is also palpable, in a pre-partition Old Delhi steeped in Urdu poetry. Yet Shamsie's voice is clear and compelling, with a welcome spareness, free of the sometimes cloying archness of earlier books.

The historical threads between Nagasaki and Guantánamo are implicit, though crucial. The atomic age marked the start of the cold war, fought hot in proxy wars from Vietnam to Afghanistan, with blood spilt by the superpowers' hi-tech weaponry. As Abdullah says bitterly, "My brother died winning their Cold War." In Hiroko's view, all it takes to wipe people out without scruple is to "put them in a little corner of the big picture" - whatever the "war" in the frame. A similar logic informs a chilling conversation about interrogation techniques. "What wouldn't I do if I thought it was effective?" Harry muses. "Almost nothing. Children are out of bounds. Rape is out of bounds. But otherwise ... what works, works." Tellingly, he asks not to be quoted to his daughter.

The identity of the Guantánamo captive remains unclear till the powerful denouement, as events unfold with a malign logic whereby even a man's stooping for a cricket ball can be fatally misconstrued. Any reader anticipating a predictable yarn about the radicalisation of Islamist youth may feel cheated. Far more, I suspect, will feel challenged and enlightened, possibly provoked, and undoubtedly enriched.

To order Burnt Shadows for £13.99 with free UK p&p call Guardian book service on 0330 333 6846 or go to theguardian.com/bookshop

• Fiction
• reviews

ncG1vNJzZmivp6x7tbTEoKyaqpSerq96wqikaJqfpLi0e5FpZ3JnnZa%2FcHyWaJmuqp6perS0wJ2msKtdoK6utcuaZKygkaLAqrGMq5yvoZWs