The map of Europe was shaped in the 20th century by complicity and disappearance. Mass murders. Expulsions. Colonisation. Countries vanished; whole peoples exterminated and displaced. For Europeans, this is the story of our continent, although rarely the version of the story we choose to say out loud. For Inara Verzemnieks, as the granddaughter of Latvian refugees who settled in the US, it’s the story of her family. Among the Living and the Dead is her effort to recover that family history – splintered as it is by war, migration, shame and loss – and put the unspeakable into words.

It is, like all attempted redemptions, both partial and painful. Renowned for her journalism in the Oregonian newspaper, she begins as any reporter should: by going to the scene, in this case the family farm in Latvia. Here, “the door to the little house opens, and I see my grandmother. Of course, by this time, my grandmother, the woman who raised me, has been dead for almost five years.” The occupant of the farm is in fact Ausma, sister of Verzemnieks’s grandmother Livija, and it’s an early lesson that will be repeated again and again. Time telescopes, and memory seduces; but whatever you’re trying to get back to is always already gone.

That’s a particularly poignant truth for the Latvian diaspora – or anyone whose origins lie in what Timothy Snyder has called the “bloodlands”, those states in eastern Europe that were barely established before suffering conquest and reconquest by Nazi Germany and the Soviet Union. Verzemnieks’s grandparents were nostalgic for Latvia, and like many children of émigrés, she attended special summer camps where she learned the language, dances and stories of the old country. But the culture they were preserving belonged to a nation that no longer existed: Latvia had been absorbed into the USSR and erased from the map. They lived “like fish trapped beneath the ice of the river in winter, suspended in this new half-life, caught between”.

And if they had been able to go back, what ghosts might have risen from that landscape of “black earth hastily tamped down over moss”? Verzemnieks’s grandfather will say that he fought in the second world war as a conscript in the Latvian Legion. What he won’t say is that this means he fought for Germany, in one of the areas where the Holocaust was most comprehensively prosecuted. By the end of 1941, almost every single one of Latvia’s 70,000 Jews had been murdered, mostly shot and buried in that black earth. Even if her grandfather wasn’t a direct participant in the pogroms, Verzemnieks knows he wore the uniform. He must have seen his neighbours vanish, and not resisted.

In her memoir In the Darkroom, Susan Faludi tells the story of her Hungarian-Jewish father, a hero who turned out to be a kind of monster. He pulled off a breathtaking rescue by imitating a Nazi, then later resettled in the US where he perpetrated grim paternal violence against his family. Verzemnieks’s grandfather is the other side of that complexity: the ordinary man who turns out to have gone along with extraordinary evil. It is the more salutary tale in some ways, because almost nobody in the bloodlands did resist collaboration. Antisemitism flowed easily.

When the Soviets occupied Latvia, Livija decided that, as the wife of a now-enemy soldier, she had to leave with her children if they were to survive. Verzemnieks’s account of her grandmother’s journey to the US is as tense as it is gruelling, Livija’s survival driven by determination but decided by chance. Meanwhile, her sister Ausma chose to stay, willingly bonding herself to her mother and brother when the family was exiled to Siberia – they were deemed to be “kulaks” – and their farm appropriated by the state. It’s almost unbearable to read about the deprivation they suffered; the endurance of both sisters is almost miraculous.

But the cost of that endurance is an unrecoverable breach as they live in different continents – Ausma under communism and Livija in middle-class America. They write each other letters telling “stories not about what really happened, but designed to help you guess what really happened when what really happened was impossible to say”. Verzemnieks’s account is personal, but by writing about national identity and asylum her book addresses our most urgent political questions. It insists with quiet elegance that, though the past eludes us, we cannot elude our past. Europe is haunted still by violence and culpability. As resurgent nationalism and antisemitism across the continent show, the unspeakable can rapidly become the normal.

• Among the Living and the Dead by Inara Verzemnieks (Pushkin, £16.99). To order a copy for £14.44, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.