Dr Henry Jekyll's enthusiasm for science and his selfless acts of service have made him a much-admired man. He becomes fascinated with the two contrasting sides of human nature, and he becomes obsessed with the idea of separating them. After extensive work in his laboratory, he devises a formula that does indeed allow him to alternate between two completely different personalities, his own and that of a brutish, lascivious person whom he names Hyde. It is not long before the personality of Hyde begins to dominate Jekyll's affairs.