In the first of three programs, Primal Instincts confronts anger. From violent crime to road rage and domestic violence, anger has much to answer for. Humans are one of the few species that kill their own and it's usually because of anger. The primal power of anger is one of the most complex human emotions, this program examines how science is exposing the inner workings of our deepest drives and challenging the very understanding of our most destructive emotion. Primal Instincts follows the U.S. landmark legal case of Jimmy 'the Fuse' Filliagi who claimed a controversial biological defence. Jimmy claimed he was "born bad" and "genetically predetermined" to bouts of anger. Tests showed he had the worst possible combination of neuro-chemical function - his dopamine response was high, while his serotonin level was abnormally low. The program also examines how a simple argument changed the life of a Melbourne landscape gardener.