May, 1944. This is the story of the Polish fighting force and their unlikely four-year journey to the frontline in Italy from the Siberian gulags, and via much of the middle east and North Africa. The start of the Second World War is famous for the imagery of German forces pouring into Poland from the west in early September 1939. By the middle of that month, the country was also invaded from the east by the Soviet Union. In just a few weeks Poland had been effectively wiped off the map, with millions of people displaced, and many now taken prisoner by either the Nazis or the Soviets. Many were liberated following the Battle of Barbarossa in 1941, where they then made a 2,000-mile journey south, largely on foot, to re-join the Allied war effort. In Monte Cassino, south of Rome, James Holland is on the ground with historian Alexandra Richie. When the Poles finally arrived at the Gustav Line in 1944, they were thrown into one of the bloodiest theatres of the war.