In the spring of 1940, following the invasion of Poland by Russia's Red Army in 1939, up to 20,000 Polish officers and soldiers were executed by Stalin's secret police. The men were imprisoned in three POW camps, one of which was based in the Katy? forest. Working from a novel by Andrzej Mularczyk and real life accounts, "Katy?" tells the story of four fictional families, forever separated from one another in 1939. A brutal and devastating work, it also received an Oscar nomination for Best Foreign Language Film in 2008.