Cato Bontjes van Beek was born on November 14, 1922, in Bremen and grew up as the eldest of three children in the German artists' village of Fischerhude. Her parents, Olga and Jan, were active in the art world and encouraged discussions about art and politics within the family. From 1931 to 1933, Cato lived with her family in Amsterdam but returned to complete her schooling. In 1937, she spent eight months as an au pair in England, where she learned English and earned her glider pilot’s license.

After returning to Germany, Cato trained in accounting and worked briefly in Bremen. In 1939, she moved to Berlin, where her father had started a ceramics workshop. Since her parents had divorced, she wrote letters to her mother, expressing her views on life, the importance of holding onto ideals, avoiding self-pity, and pursuing goals with determination.

Gradually, she became more aware of the consequences of the Nazi regime. She witnessed anti-Jewish actions and heard rumors of murders in the ghettos. In 1940, she was conscripted into labor service in Blaustein (now Siniec, Poland), where she eventually ended up in the infirmary due to physical complaints. After her discharge in September 1940, she returned to her father in Berlin. There, she met Harro and Libertas Schulze-Boysen and became involved in their resistance network, later known as the Rote Kapelle. Cato helped people go into hiding, distributed travel documents, and spread leaflets and posters exposing the truth about events in the East and calling for resistance against the regime.

On September 20, 1942, she and her father were arrested by the Gestapo. In a large-scale trial against over 130 suspects, dozens of death sentences were handed down. Her father was released due to lack of evidence, but Cato was sentenced to death. Despite this, she remained clear-minded and determined until the end. In letters to her mother from prison, she wrote about her longing to live: "Nur leben will ich, leben, leben!" ("I just want to live, live, live!"). She also secretly exchanged notes with fellow prisoners. In her final letter to her mother, after all pleas for clemency were personally rejected by Adolf Hitler, she wrote that she had come to terms with her fate.

On August 5, 1943, Cato Bontjes van Beek was executed by beheading. She was denied a burial, and her body was given to a university. At least 57 members of the Rote Kapelle suffered the same fate.