After the death of her beloved husband, Katrin, a literary biographer, copes with the loss by writing his personal history. While researching the letters and journals he left behind, however, she comes to the devastating conclusion that his life before their marriage was far richer than the one they shared. To understand and recreate the period of his greatest happiness - a period of intense friendship and love in the fall and winter of 1968, with a young French woman named Monique - Katrin embarks on a heartbreaking journey to discover the man she never fully knew.