In an unnamed country on the brink of civil war, an odd relationship slowly blossoms between sweet-natured Saeed, an advertising agency employee living with his doting parents, and Nadia, who lives alone, rides a motorcycle and, despite swathing herself in long black robes, does not pray.

Their love story plays out against a bleak backdrop of mounting violence between government and rebel forces, as bombings and shootings grow more rampant, and society dissolves into chaos and paranoia.

Saeed and Nadia soon start looking for a way out of the country, after hearing rumours of magical doors that can transport people to distant lands.

These mysterious portals - which the authorities are racing to discover and block off - remove much of the drama of the protagonists' flight west, away from a war-torn homeland; there are no long, arduous journeys across land and sea here.

But Mohsin Hamid spins a sobering tale anyway, not of the physical obstacles that dog refugees on their search for safety, but of the psychology of refugees once they succeed in their bid for freedom.

In leaving their homes behind to survive and rebuild their lives, they have condemned themselves to exile in unfamiliar countries where locals are organising riots to protest against the influx of immigrants.

Saeed and Nadia have fled a home being dissolved by war, but arrive again and again in societies being torn apart by hatred and prejudice.

They are haunted by a sense of displacement and are changed in different ways by the experience; hence, they must come to grips not just with their new status as unwanted refugees, but also with the changing nature of their relationship.

The first door takes them to the Greek island of Mykonos, where they join hundreds of migrants who have set up a makeshift refugee camp near a beach frequented by wealthy tourists.

But Mykonos is not ready to accept refugees into its fold: Saeed and Nadia fail to find work and their funds quickly dwindle.

When an acquaintance shows them a new door out of the country, they accept. This sends them to London, where they squat alongside other migrants in a neighbourhood of empty mansions, which rich foreigners buy as holiday homes.

It is in London that Exit West truly shines, most clearly illustrating how differently Nadia and Saeed react to their new circumstances and how their relationship suffers as a result.

While Nadia finds herself liberated from the shackles of her homeland, seeking companionship from migrants from different lands, Saeed is beset by nostalgia, praying more to reconnect with his lost home and seeking out his fellow countrymen for companionship

Hamid writes: "Every time a couple moves, they begin... to see each other differently... So it was with Saeed and Nadia, who found themselves changed in each other's eyes in this new place."

They escape through a third door to the United States, hoping to re-establish their connection in a new country, but discover they have been forever changed.

As they live in foreign lands, their understanding of religion, nationhood and identity diverges.

They can no longer reconcile their beliefs and gently, quietly drift apart.

Unfortunately, this means the novel stutters to a weak close that some may find unfulfilling.

Still, Exit West - Hamid's fourth novel and his first in four years - is a poignant take on the refugee crisis, coming amid a tide of rising xenophobia.

While the book ends with the disintegration of a young migrant couple's dream of starting a new life together, it also closes on a note of hope.

Saeed and Nadia must go on their separate paths, but they have survived. And the societies that at first reacted with violence against them and their ilk soon realise that they are here to stay.

In this new balance being forged, Saeed and Nadia manage to carve out spaces for themselves.

At the end, the message is acceptance - something the world could do well to remember these days.

•If you liked this, read: The Silver Sword by Ian Serraillier (Vintage, 2012, $15.26, Books Kinokuniya), which follows a group of Polish children who flee to Switzerland during World War II to reunite with their parents.