From Madrid... to hell amid the chaos of World War II in Europe, Maria Millan, a young Spanish Communist, is swept up in the whirlwind of history. After losing her mother in a bombing raid on Madrid and her brother in the battle of the Ebro, she flees to France in search of refuge. But her destiny takes her further than she ever imagined. Ravensbrück concentration camp After learning, in Bordeaux, of the tragic death of her father in the defense of Madrid, she changes her identity to join the French Resistance against the Nazi occupation. After the loss of her lover, Maria will suffer a new blow: she will be captured in the Lyon roundup and transferred to the infamous extermination camp. Die Glocke, "The Bell" of time in the darkest circles of the Third Reich, Hans Kammler leads a top-secret project that could change the course of the war. With the help of Maria Orsic, a mysterious medium, he tests the control of a technology that could grant him unprecedented power: "The Bell" capable of time travel. When the war ends, Kammler flees, taking with him the secret that could change the world. In his way crosses Maria Millan, now known as Maria Sliva and KGB agent trained by Caridad Mercader, with a mission: to find him and make sure that the secret of Die Glocke, "The Bell", does not fall into enemy hands. From the streets of Madrid to the corridors of the Vatican, Maria will embark on a dangerous quest that will take her to the limit of her abilities. A dark tangle of intrigues, secrets and betrayals that will lead her to discover the hidden truth behind "The Bell" of time.