We were in the old London of end of century XIX. Mr. Utterson is a prestigious London lawyer to listened to a history of hands of his friend, doctor Enfield, who makes him wake up hiscuriosity. This Utterson begins an investigation to get to find out the true identity of Mr. Hyde, a man who appears very united to an old friend met like doctor Jekyll. Their investigations take toUtterson, first of all, to a testament written by Jekyll, in which proprietor does, in the case of their death or disappearance, of all goods to Hyde. Later the lawyer will maintain aconversation with Jekyll, the one that will ask to him that it forgets the subject. Later a brutal murder in the city takes place, a witness assures that the assassin has been Mr. Hyde, after a longtime search, this one does not appear, and it takes place the strange disease and later death of Lanyon, an old friend of Utterson. After long time of tranquillity, one night appears Poole, theservant of Jekyll, in house of Utterson to request aid to him. This one moves to house of its friend and after demolishing the door of the laboratory they find the corpse of Hyde next toletters written by the same Henry Jekyll. Already in house, Utterson is put to read them, in these letters explains the strange case: the doctor knew a clearly obsession: to divide the two naturesof the person (the one of the good and the one of the evil). He obtains it to this by means of a potion that Jekyll invents. When drinks it becomes a malignant being, Mr. Hyde. More and more,Hyde went adapting of its body until arriving the point in which both personages hated themselves. The proportions with which it made the potion went finishing and it did not find theappropriate substance for the potion, until this one finished, both fought the one against the other, but the end of the product arrived and the Dr. Jekyll as much as Mr. Hyde finds the death.