September 1941. On the Eastern Front of World War II, Kostya and his fellow Russian cadets are tasked with evacuating thousands of civilians out of war-torn Leningrad, to safety aboard Barge 752. While Kostya's commander initially worries that the barge may be too outdated to safely sail across Lake Ladoga, the evacuation is completed, even allowing Kostya time to smuggle his fiancé, Nastya, aboard the barge to join him on the journey. But catastrophe quickly finds them