Two important events

Enfield chanced upon a deformed, short man who trampled a girl in the street on her way to fetch a doctor. The girl's family and Mr. Enfield catch the mysterious man and instead of getting the police, decide to force him to give the girl's family money. This sets the backstory and introduces the major conflict. Another important event is when Jekyll, "had gone to bed Henry Jekyll, [and] had awakened Edward Hyde." Jekyll was alarmed that he transformed into Edward Hyde without the assistance of the potion, and became concerned that the character of Hyde might irrevocably take over.