The Jewish Weizenbaum family left Germany and their family furrier business in 1936, and started all over in Detroit, Michigan, when Joseph was 13. At a time when the German capital, Berlin, was struggling with famine after World War II, Joseph Weizenbaum was soldering and programming the world's first computers. He created the first banking computer in the world, was perhaps one of the first computer nerds ever and pursued an unprecedented career at the Massachusetts Institute of Technology, the "mighty" MIT in Cambridge, where he invented the first virtual persona, ELIZA/DOCTOR, a program that engaged humans in conversation with a computer. Later, Weizenbaum was branded as a heretic when he began to criticize his colleagues in public. After retiring as a full professor at MIT, he left the United States and is now living in Berlin-Mitte again. Weizenbaum eventually became a "preacher", strictly demanding responsibility of each individual scientist, condemning war and arguing that mankind have become insane. The film spans 9 decades of Joseph Weizenbaum's life. It provides a stage for his humorous narrative depicting a World of Yesterday while reflecting on the dawn of the computer age. It follows 84-year-old Weizenbaum on some of his numerous public lessons, effortlessly entertaining overcrowded lecture halls. The old man is an up-to-date chronicler, a chief witness against militarism and the myths of technological progress, but he remains a modest, funny and most reflective story teller. The story line of his life sketches a gigantic picture, too large for a documentary, large enough to easily fill a novel.