In this true story, Armande Martel, a young nun from Quebec, is arrested by the Germans in 1940 during a stay at her religious order's mother house in Brittany. She spends the war years in a German concentration camp. After her return to Canada, she leaves the Church, finds the love of her life in Montreal, and adopts Lise Dion.
Growing up, Lise is familiar with only a few facts of her mother's past. It's when she clears her mother's small apartment after her death that Lise Dion discovers the key to the blue trunk, which was always locked. This key unlocks the mystery of Armande's early life, and Lise decides to write The Secret of the Blue Trunk.