The movie revolves around Norbit Ryan (played by Robert Downey Jr.), a man who was once a fat, awkward, and bullied kid. Years later, Norbit becomes a slim, successful, and somewhat happy man. However, his life takes a drastic turn when his childhood sweetheart, Rasputia (also played by Robert Downey Jr.), whom he had been trying to get rid of, comes back into his life with her three children. To make matters worse, Rasputia is now a grossly obese and controlling woman. The complexity of Norbit's life increases when he falls in love with a beautiful woman named Nora (played by Kate Hudson).