Based on a true story - May 1945, Königsberg. The legendary capital of East Prussia serves as the starting point for an odyssey across the mystical Gotland to Småland. Sergeant Martin Greven, his young love Greta Sandberg, and 10-year-old Lena have no idea that they are being hunted by a secret society because of a key to one of the world's most mysterious treasures. Meanwhile, Martin's comrades are interned in Sweden, with the promise that they will be released back to Germany. They are unaware that the government in Stockholm has long had other plans. What follows is utterly incomprehensible. Bloody Friday is one of the most traumatic experiences in Sweden during the post-war period. In Germany, however, few know of the dramatic events surrounding the German soldiers. Embedded in these historical occurrences is a story of love and hope, of life.