"We had become bottom-feeders, living off filth and rot." The transformation from daughter of a Lithuanian university provost into a starving scavenger, accustomed to witnessing acts of unimaginable cruelty, worked half to death and stripped of all dignity, takes a matter of weeks. Ruta Sepetys gives readers no more time to prepare themselves for the horrors of the work camp than the NKVD (the Soviet secret police) give 15-year-old Lina and her family time to pack their suitcases. "They took me in my nightgown" is the first line of this remarkable debut.

Based on first-hand accounts, Sepetys's YA novel charts an immense journey, in every sense, from a middle-class home in Lithuania to a gulag at Trofimovsk in the Arctic Circle. The bare facts about the genocide perpetrated by Stalin are nigh on impossible to take in. On the other hand, have a lucid 15-year old describe a Siberian winter, or how the NKVD waited outside a hospital for the next victim's umbilical cord to be cut, then we can glimpse something of what occurred.

Lithuania, Latvia and Estonia disappeared off the map in 1940 and did not reappear until the collapse of the Soviet Union in 1990. When the survivors of the work camps were finally allowed home (most perished), the permanent, threatening presence of the KGB ensured that their stories could not be told. Lina documents her experiences in words and drawings and buries them in a jar hoping that her testimony will eventually see the light of day.

The storyteller who wishes to bring such a past to life, "make it real" by fictionalising it, clearly shoulders an immense responsibility. Sepetys draws heavily on the heartbreaking testimony of survivors. She must have faced some tough narrative choices. Is it your duty, for example, when writing for a teenage audience, to sift through the cinders of such a hell to find meaning and consolation in some form? For Sepetys love certainly redeems: love of country, love of family, love of fellow survivor. And it is in the small gestures that it finds its expression: beet smuggled in underwear under the gaze of the guards, sharing rations with strangers, asking the name of one's tormentor.

Readers will inevitably compare Lina's (albeit fictional) first-person narration with that of Anne Frank: the clear-sighted intelligence and courage, the focus on the minutiae of life, the fears and the foibles of one's fellow human beings. A major difference is that we read Frank's words knowing that she is doomed. Lina, however, tells us at the outset that "It was the last time I would look into a real mirror for more than a decade." So the tension works differently here: what new horrors will Lina have to bear?

The fluid narrative is compelling yet restrained. The horrors of the cattle trucks and the gulag, the cruelty of the Soviet guards, are all there. Minor characters are memorably and vividly drawn, and the first half of the book, in particular, roars along. Dr Johnson wrote that the only end of writing is to enable readers better to enjoy life, or better to endure it. Hard to read but even harder to stop reading, there is no doubt into which category this tremendous first novel belongs.

Linda Buckley-Archer's Time Quake trilogy is published by Simon & Schuster.