When the United States entered World War II (December 7, 1941) William H. Turcotte applied to and was accepted into the Army Air Corps, eventually becoming an aerial navigator with the 332nd Squadron, 91st Bomb group (July 1943). He participated in fourteen bombing raids into German-held territories. During the last raid, October 9, 1943, Turcotte's B-17 bomber was involved in an air battle and crashed near Anklem, Germany. Turcotte and the plane's bombardier managed to bail out of the plane, landing in a rutabaga field. They were subsequently taken into custody by townsmen and handed over to the German Luftwaffe. On October 22, 1943, Turcotte arrived at Stalag Luft III in Sagan, Germany, where he would spend the next eighteen months. His internment at the camp's south compound coincided with "The Great Escape" of seventy British POWs, which took place on March 25, 1944, at the north compound. Turcotte referenced a shooting incident involving a "beserk" camp guard two days after the escape and reproduced a scare card subsequently posted by the Germans in all prison camps.
The War Prisoners Aid Division of the Young Men's Christian Association produced blank diaries (log books) that were distributed to Prisoners of War in Red Cross care packages. Turcotte's log book contains colored pencil drawings of "Kriegie" (German slang for a Prisoner-of-War) living conditions, food, and activities. The drawings, while humorous, do convey the harsh living conditions Turcotte and his fellow prisoners faced, as well as their ingenuity. This is particularly shown in the illustrations of "KLIM Tin Ware." These were items made from the reclaimed metal from one-pound milk and jam cans. Turcotte drew portraits of his roommates in Room 4, Block 130, at Stalag Luft III. These are accompanied by their personal information and nicknames. He also wrote entries discussing the invasion of Germany, the prisoners' removal to Stalag Luft VII-A in Moosburg, Germany, and the eventual liberation of the prisoners on April 29, 1945.