In 1939, Gustav Kleinmann, a Jewish upholsterer in Vienna, and his teenage son, Fritz, were sent to Buchenwald. When Gustav was set to be transferred to Auschwitz, Fritz refused to leave his side. Based on Gustav's secret diary and meticulous archive research, this book tells his and Fritz's story for the first time - a story of courage and survival unparalleled in the history of the Holocaust. For anyone captivated by "The Cut Out Girl" or "The Tattooist of Auschwitz".