Lily Briscoe sits alone at the breakfast table early in the morning, unable to understand or express her own feelings about Mrs. Ramsay's death. Today, there will be an expedition--Mr. Ramsay, Cam, and James are going to the Lighthouse, though the children are late to depart and Mr. Ramsay has lost his temper because Nancy forgot to order the sandwiches. Lily feels "cut off from other people" and like a stranger in this house, lacking attachments and relations. The world seems aimless and chaotic now that Mrs. Ramsay, Prue, and Andrew are dead, and she feels strangely numb to these changes.
When Mr. Ramsay passes by, Lily pretends to drink from her empty coffee cup to avoid his penetrating gaze. Suddenly, Lily remembers that the last time she sat at this table, ten years ago, she resolved to complete her painting by moving the tree closer to the middle. She did not, however, complete it, so she decides to finish it now. She sets up her chair and easel on the lawn in what she believes to be the exact location of her previous setup, and she suddenly knows what she wants to do with the painting.
But Mr. Ramsay's presence on the terrace paralyzes her and makes her unable to paint. She stalls, trying to avoid his gaze and his declaration--much as he had declared the night before--that she would find them "much changed." He also appears as domineering toward his children, for he essentially demanded that James and Cam go with him on this trip to the Lighthouse, and Lily feels that their spirits are being subdued.
Setting her clean canvas on the easel, she hopes to ward off Mr. Ramsay, but she finds it simply impossible to work while he is at such a close distance. He silently demands something of her that she cannot give, something that Mrs. Ramsay had given. Suddenly, she feels a surge of anger directed at Mrs. Ramsay for dying, for having left her here, and for leaving behind a feeling of emptiness. Nevertheless, she is convinced that she is, in fact, numb to Mrs. Ramsay's death, and she wonders why she tries to make herself feel emotions that are not real.
Finally, she decides that the cost of insincerity is worth placating and dismissing Mr. Ramsay, so she decides to recreate the look of rapture, sympathy, and delight that Mrs. Ramsay had demonstrated so many times. Mr. Ramsay approaches Lily, and she resolves to give him what she can.
Mr. Ramsay notes that Lily looks somewhat shrivelled, and he approaches her, not really conscious of his hope to evoke her sympathy. Irritated that Lily avoids direct interaction by looking at the sea and speaking of the Lighthouse, Mr. Ramsay emits a loud groan, and Lily feels guilt and self-hatred for not responding to it with the sympathy that she thinks other women would. Mr. Ramsay begins to explain the significance and difficulty of this trip to the Lighthouse, for Mrs. Ramsay used to send gifts to the men and children who lived there. He talks of how exhausting and painful such trips are, and Lily feels overwhelmed and tortured by his need for her sympathy. She becomes anxious for him and the children to take off on their expedition. She stands in silence, feeling herself an ineffectual woman for not being able to fulfill the emotional duties traditionally expected of women; she is failing to console him in his self-pity.
Grasping for something to say, she comments on his beautiful boots, and he is pleased. This restorative interaction leads them to a peaceful reconciliation. Suddenly Lily is overcome with genuine sympathy for him, but just as she is finally able to express it, Cam and James solemnly emerge from the house. Lily feels frustrated, wishing that they would provide the sympathy that she almost entirely failed to give. The three travelers proceed to the boat with the brown paper parcels, leaving Lily feeling impressed by the melancholy troupe, inferring that they are bound by some common feeling. Lily now sees Mr. Ramsay's unornamented beauty and newly appreciates his commitment to bare truth.
Lily is both relieved and disappointed that the three Ramsays have left. As she looks at her canvas, she sheds the "disorderly sensations" of the previous several minutes and tries to remember how she originally envisioned this painting. She has extreme difficulty actually making the first stroke, knowing that "one line placed on the canvas committed her to innumerable risks, to frequent and irrevocable decisions," but she knows it must be done, and she executes a quick stroke. She paints rthymically, stepping back to survey the brown lines. She always feels a sense of complete vulnerability before painting, "like an unborn soul."
She speculates that her work will only be hung in the servants' bedrooms or stuffed under a sofa. She feels insecure, wondering why she should paint if no one will view her work. She tells herself that she is not, in fact, capable of creating.
Suddenly, her artistic faculties take over and she begins painting almost unconsciously, without any disturbance from thoughts of the outer world. She remembers Charles Tansley's discouragement, but she feels a rising tenderness for him as she recalls a day that she spent on the beach with him and Mrs. Ramsay. Mrs. Ramsay was writing letters and watching as Lily and Mr. Tansley skipped stones across the water, getting along quite well. Lily imagines that Mrs. Ramsay was somehow responsible for this scene, as well as for Lily and Mr. Tansley's brief episode of communion. Mrs. Ramsay's simple presence stripped an individual of anger and irritation and brought people together.
This recollection refashions Lily's memory of Mr. Tansley more sympathetically, and Lily realizes that, in a sense, this refashioning represents Mrs. Ramsay's own persisting creation of a work of art. Both Lily and Mrs. Ramsay were, in their separate ways, "making of the moment something permanent." This revelation offers Lily a sense of shape and stability amidst chaos, and she feels that she owes it all to Mrs. Ramsay. Walking to the end of the lawn, she sees a boat apart from the others with its sail being hoisted. She knows that this is the Ramsays' boat, and she watches as it passes the other boats as it sails out to sea.
In the section called "The Lighthouse," time returns to its original pace in the novel and reality is, once again, defined by the consciousness of the characters. In fact, the first and third parts of the novel seem to collapse into each other, completely obliterating the middle section. The novel has moved from subjective time to linear chronological time and back again. "The Window" ended at night, with the characters going to sleep and entering a period of darkness. Now, "The Lighthouse" opens with Lily sitting at the breakfast table, and the reader almost feels as though this could be the very next day. However, it is not the very next day--the period of darkness has lasted not for one night but for ten years--and the life of the Ramsays has been irrevocably altered, now that three members of the family, including Mrs. Ramsay, are dead.
Despite Mrs. Ramsay's physical absence, her presence remains in the house and in the memories of those who knew her best. During "Time Passes," Mrs. McNab often vividly envisioned Mrs. Ramsay walking toward the house, tending to her garden. Now, in "The Lighthouse," Lily keeps looking over at the drawing-room steps, imagining and sensing Mrs. Ramsay's seemingly permanent presence. The novel is infused with her consciousness throughout "The Window," and this final section reveals that her consciousness has persisted as a central consciousness even after her death.
Though Mrs. Ramsay's thoughts are not directly expressed anymore, her influence is apparent, especially her influence on Lily. Some essential, invisible aspect of her character is imparted through Lily, who even begins to feel a sympathy for Mr. Ramsay that she was never able to feel while Mrs. Ramsay was alive. In this way, Lily embodies some of the beloved woman's "wedge-shaped core of darkness" in its most positive construal. In a sense, this reproduction of Mrs. Ramsay's individual creative power represents the fulfillment of Mrs. Ramsay's wish for permanence and stability.
Just as Mr. Ramsay's anxiety centers around the regret that his life's work will never bring him a sense of lasting recognition, Lily Briscoe worries about the long-term status of her paintings. She is generally considered a rather mediocre artist, and her concerns that her paintings will be thrown into attics and otherwise forgotten are not unfounded. Her emotional investment in the endurance of her own work produces the same general sense of unfulfillment for Lily that their own anxieties and efforts do for the Ramsays. However, unlike the Ramsays, Lily is eventually able to abandon the desire for permanence, and she comes to embrace the uncertainty and instability of experience. Somehow, the distant sight of the Ramsays on the boat sparks a pivotal epiphany, when Lily's creative energy swells to outpouring. The process of removal from them and relinquishment of her anxiety results in the unveiling of Lily's most sympathetic feelings for the Ramsays, and these feelings inspire her vision.