Dr. Jekyll and Mr. Hyde

"This Master Hyde, if he were studied,' thought he, 'must have secrets of his own; black secrets, by the look of him; secrets compared to which poor Jekyll's worst would be like sunshine.'" The Strange Case of Dr. Jekyll and Mr. Hyde
When Edward Hyde traples an innocent girl, two bystanders catch the fellow and force him to pay reparations to the girl's family. A respected lawyer, Utterson, hears this story and begins to unravel the seemingly manic behavior of his best friend, Dr. Henry Jekyll, and his connection with Hyde. Utterson probes into both Jekyll and his unlikely protégé, increasingly unnerved at each new revelation.