It follows the Stalinist repressions of the mid-20th century and follows the life of a teenage girl Lina as she is deported from her native Lithuania with her mother and younger brother, and the journey they take to a Gulag labor camp in Siberia.

[3] Between Shades of Gray is partly based upon the stories Sepetys heard from survivors of Soviet repressions in the Baltic states during a visit to her relatives in Lithuania.

[4] Sepetys decided she needed to write a fiction novel rather than a non-fiction volume as a way of making it easier for survivors to talk to her.

[5] Lina Vilkas is introduced as a young artist living comfortably in her home in Kaunas, Lithuania, with her loving family.

Separated from her father and forced onto a crowded and dirty train car, Lina, along with her mother and her younger brother Jonas, slowly makes her way north to a work camp in the coldest reaches of Siberia.

The family befriends fellow Lithuanian deportees including Andrius Arvydas (who later becomes Lina's love interest), Mr. Stalas (referred to as the Bald Man, who is secretly Jewish and adds a touch of humour because of his terrible advice and short temper), Mrs. Grybienė, Mrs. Rimas, and Aleksandras Lukas (a gray-haired man who was once a lawyer, often seen winding his watch, who is the voice and soul of reason).

The book's ending is somewhat open-ended, although it is revealed in the epilogue that Lina and Jonas survive and are held there for ten more years.

[7] Publishers Weekly praised Between Shades of Gray, calling it a "harrowing page-turner, made all the more so for its basis in historical fact".