In a Land of Forest and Darkness is a story of coming of age in the shadow of the Holocaust. Sara Lustigman was fifteen years old when the Nazis occupied her small town in eastern Poland, and her whole world shattered. Sara's personal story provides a glimpse into the lives of her family, friends and townspeople, Jewish and non-Jewish alike, from immediately before the war and during the years of the Nazi occupation: persecution, ghetto, slave labor, roundups, the "Final Solution", escape to the forest, resistance groups and Soviet partisan units. Major events are portrayed alongside personal experiences – support in times of need, acts of betrayal, loves and disappointments, and often unsupportable dilemmas. All are described from a personal point of view, with frankness and sensitivity.

The book also recounts the tale of Sara's future husband, Michael (Misha) Omelinski from Brest Litovsk. Misha too survived miraculously, and after hair-raising adventures joined a Soviet partisan group in the Polesia woods (in Belarus of today) and became a fierce partisan and fighter. It was in those woods that the two youngsters met and tied their fates until the end of the war and beyond.