Dorian is awoken by Victor, his servant, after having slept until 1:15 in the afternoon. He sees that he has received a letter from Lord Henry, but leaves it unopened. He feels refreshed and eats breakfast happily, the previous night feeling like nothing more than a dream. His pleasant afternoon is interrupted, however, when he sees the screen that he has thrown over the portrait. He thinks himself foolish for imagining that the painting might have changed, but decides to check it again just to make sure. Nervous that he might be acting strangely, he throws Victor out of the room, locks all of the doors, and draws the curtains. Sure enough, "It was perfectly true. The painting had altered." He wonders how this could possible, whether there is a scientific explanation, or a darker, metaphysical cause for the change. The cruel expression on the face in the portrait reminds him of his poor treatment of Sibyl. Stricken with guilt, Dorian writes her a passionate love letter, filling "page after page with wild words of sorrow and wilder words of pain."
Writing the letter is deeply cathartic. As soon as he finishes, Lord Henry arrives. Dorian tells him that although he saw Sibyl and was brutal towards her, he doesn't regret any of it, since "It has taught me how to know myself better." Henry is delighted to find Dorian in good spirits, but when the young man tells him that he plans to cleanse his soul by marrying the poor actress, it is clear that there has been a misunderstanding. Sibyl Vane, as Henry had written to Dorian in the unopened letter, has killed herself with poison.
Henry says that there will be an inquest, but that Dorian has nothing to worry about since nobody saw him go backstage or leave the theater, and since Sibyl never even told anyone her fiancÃ©'s real name. Henry urges Dorian not to get involved with the situation, as such a scandal would destroy his reputation. He asks Dorian to come see the opera with him that night. After his initial shock passes, Dorian responds to the news of Sibyl's death with a strange detachment. "So I have murdered Sibyl Vane," he thinks, "as surely as if I had cut her little throat with a knife. Yet the roses are not less lovely for all that."
Under Henry's direction, Dorian comes to appreciate Sibyl's death as "a wonderful ending to a wonderful play." Dorian is briefly disturbed by his emotional detachment, but Henry soon assuages his guilt, saying that life's tragedies often "hurt us by...their entire lack of style." Since Sibyl died so dramatically, and for such a pure purpose as love, the situation is actually one, Henry believes, that Dorian should take satisfaction and pleasure in. Henry goes so far as to state that since the girl was only ever alive on stage, and since Dorian's love for her was rooted in his admiration for the various heroines she portrayed, that "The girl never really lived, and so she has never really died...don't waste your tears over Sibyl Vane. She was less real than [Shakespeare's characters] are." Dorian thanks Henry for being such a good and true friend.
Henry leaves, and Dorian again looks at the picture. The mean sneer has not shifted, making Dorian think that it had "received the news of Sibyl Vane's death before he had known of it himself." After further contemplation, Dorian consoles himself by thinking that since the picture displays his true character, it must "bear the burden of his shame," thus leaving him to enjoy a guilt-free life. He sees no reason to consider why the picture changes, and decides to allow himself to simply be entertained by its progress. The chapter ends with Dorian leaving to meet Lord Henry at the opera.
Once again, Dorian displays alarming capriciousness and a disturbing blindness to his own vanity. He writes to Sibyl in a passion, taking all of the blame for his actions, but the narrator comments that "there is a luxury in self-reproach." He takes pleasure in his confession, privately praising his own "selflessness". He falls into a brief spell of grief upon hearing the news of Sibyl's suicide, but proves to be far from inconsolable. Lord Henry, playing the devil to Dorian's Faust, shows him the means by which to transform his pain and guilt into a new, pleasurable experience, for which only the portrait will pay the price.
In this chapter, the symbolic significance of the portrait is clearly spelled out for us: "here was a visible symbol of the degradation of sin...an ever present sign of the ruin men bring upon their souls." This realization prompts Dorian to exclaim that he "can't bear the idea of my soul being hideous." Dorian fears physical ugliness; in other words, it is vanity, not morality, that defines Dorian's relationship with his soul. A similar type of selfishness appears when Dorian writes his love letter to Sibyl. We are told that "There is a luxury in self-reproach...When Dorian had finished the letter, he felt that he had been forgiven." Even in the throes of guilt, Dorian does not need Sibyl to grant the forgiveness that only she can rightly give, nor does it occur to him that Sibyl would do anything other than immediately accept his apology and agree to be his wife.
Dorian's comment that Sibyl's death seems "to be like simply a wonderful ending to a wonderful play" continues the theme of life imitating art. It also recalls Dorian's obsession with the characters that Sibyl portrayed. He became disappointed in her when she tried to be her own person, and rejected the falseness of playing a role. Now, her death has given Dorian the ability to once again view Sibyl as a character in a play. When Lord Henry encourages this interpretation of the tragedy, he ensures that Dorian passes the point of no return on his descent into immorality.
Dorian's statement that he has "murdered her...as if I had cut her little throat with a knife" not only displays a disturbing tendency to relish in unnecessarily morbid details, but also foreshadows Basil's murder in chapter 13, and recalls Basil's threat to destroy the painting with a knife in chapter 2. The image of death by stabbing hovers in the air throughout the novel.
This chapter also contains the closest thing Wilde offers as to an explanation of how the portrait has acquired such metaphysical properties. However, it is not actually an explanation at all, but merely idle conjecture from Dorian: "Was there some subtle affinity between the chemical atoms, that shaped themselves into form and colour on the canvas, and the soul that was within him? Could it be that what the soul thought, they realized? - that what it dreamed, they made true? Or was there some other, darker reason?" Dorian is briefly disturbed by the possibility that black magic is at work, but he soon shrugs off this fear, and the question of how and why the portrait changes is never again raised.