This paper is a case study of a bilingual patient who had split-brain surgery in 2003 to treat a chronic case of epilepsy since childhood. It investigates this patient after the surgery. Evidence showing the complementary nature of the two hemispheres will be provided and analyzed. It is concluded that the two hemispheres work in a constant complementary manner. This study is a reconfirmation of the unifying role that the corpus callosum plays in prosecuting the functions of the left hemisphere and the right hemisphere in light of the general belief that the two hemispheres work together.