Dr. Jekyll and Mr. Hyde is a four-act play written by Thomas Russell Sullivan in collaboration with the actor Richard Mansfield. It is an adaptation of Strange Case of Dr Jekyll and Mr Hyde, an 1886 novella by the Scottish author Robert Louis Stevenson. The story focuses on the respected London doctor Henry Jekyll and his involvement with Edward Hyde, a loathsome criminal. After Hyde murders the father of Jekyll’s fiancée, Jekyll’s friends discover that he and Jekyll are the same person; Jekyll has developed a potion that allows him to transform himself into Hyde and back again. When he runs out of the potion, he is trapped as Hyde and commits suicide before he can be arrested.