Every Sunday, Mr. Utterson, a prominent London lawyer, and his distant kinsman, Mr. Richard Enfield, take a stroll through the city of London. Even though to a stranger's eyes, these two gentlemen seem to be complete opposites, both look forward to, and enjoy, their weekly stroll with one another.

One Sunday, they pass a certain house with a door unlike those in the rest of the neighborhood. The door reminds Mr. Enfield of a previous incident in which he witnessed an extremely unpleasant man trampling upon a small, screaming girl while the strange man was in flight from something, or to somewhere. The screams from the small girl brought a large crowd, and various bystanders became incensed with the indifference of the stranger, whose name they discovered to be Mr. Edward Hyde. Enfield can recall the man only with extreme distaste and utter revulsion. The crowd forced the man to make retribution in the form of money, and they were all surprised when he returned from inside the "strange door" with ten pounds in gold and a check for ninety pounds. They held him until the banks opened to make certain that the check was valid because it was signed by the well-known Dr. Henry Jekyll, and they suspected that it was a forgery. To their amazement, the check was valid.

That evening, in his apartment, Mr. Utterson has further reason to be interested in Mr. Hyde because Dr. Jekyll's will has an unusual clause that stipulates that Edward Hyde is to be the sole beneficiary of all of Jekyll's wealth and property. Utterson goes, therefore, to visit an old friend, Dr. Lanyon, who tells him that some ten years ago, he and Dr. Jekyll became estranged because of a professional matter. Utterson decides to seek out Hyde, and he posts himself as a sentinel outside the mysterious door previously mentioned by Enfield. After some time, Utterson encounters the man Hyde entering the door, and he initiates a conversation with him. Hyde suddenly becomes highly suspicious of Utterson's interest in him and quickly retreats inside the door. Utterson walks around the block and knocks at the front door of Dr. Jekyll's house. Upon questioning the butler, Poole, Utterson discovers that Edward Hyde has complete access to Jekyll's house.