In a summerhouse on the Isle of Skye, James is enraged when Mr. Ramsay insists he won’t get to go to the Lighthouse the next day. Mr. Tansley echoes Mr. Ramsay. Mrs. Ramsay tries to preserve James’ hope. She reflects on Mr. Tansley’s charmlessness, then recalls his confiding in her about his poverty. Lily struggles to paint on the lawn. She agrees to accompany Mr. Bankes on a walk and they discuss the Ramsays. Meanwhile, Mr. Ramsay argues with his wife about the Lighthouse again, aggravating James. Mr. Ramsay meditates by the sea. After walking, Mr. Bankes admires Mrs. Ramsay and Lily considers the vivacity distinguishing her beauty. Lily explains her painting to Mr. Bankes.
Meanwhile, Mrs. Ramsay wishes Cam and James could stay small, thinking she’s not pessimistic (as her husband says), just realistic. She worries about Nancy, Andrew, Paul, and Minta on their walk. After James goes to bed, Mrs. Ramsay watches the Lighthouse, thinking, a sight which saddens Mr. Ramsay. She walks with him, chatting affectionately. Mr. Bankes and Lily walk, too, discussing painting, then the Ramsays. They come upon Mr. and Mrs. Ramsay who seem suddenly symbolic in the spell of evening.
On the cliffs, Nancy, Minta, Paul, and Andrew have separated and reunited awkwardly on the sight of Minta and Paul embracing. Their return is delayed by Minta’s lost brooch, which Paul chivalrously determines to find. He has successfully proposed to Minta. Minta sobs for more, Nancy feels, than the brooch.
At the summerhouse, Mrs. Ramsay lets Jasper and Rose help her dress and is relieved when the walk party returns. Though she despairs at dinner’s start, Lily helps her manage small talk and the conversation eventually carries the night into an orderly beauty that Mrs. Ramsay believes partakes of eternity. Mr. Tansley and Mr. Bankes flounder, then find footing at the table. Lily feels burned by lovestruck Paul’s indifference, and decides not to marry. After dinner, Mrs. Ramsay coaxes Cam and James to sleep, sends Prue, Paul, Minta, Lily, and Andrew off on a walk, then joins Mr. Ramsay reading. She feels transported by a sonnet. After reading, Mr. and Mrs. Ramsay say little but still express their deep love for one another.
Nights pass, then the season. Mrs. Ramsay dies suddenly. The house stays empty. Prue marries, then dies in childbirth, and Andrew dies in World War I. Mr. Carmichael gets famous. Mrs. McNab eventually gives up on caring for the house, which falls into disrepair. Then, after ten years, Mrs. McNab receives word to prepare the house and laboriously does so. Lily and Mr. Carmichael return.
The first morning back, Mr. Ramsay forces the teenage Cam and James to go to the Lighthouse with him. Lily fails to avoid him before they leave. During an awkward conversation, Lily feels Mr. Ramsay silently pleading for her sympathy and feels like a defective woman for not giving it. Mr. Ramsay sets off with a resentful Cam and James and Lily feels guilty. She tries to paint but is distracted by thoughts of Mrs. Ramsay and questions life’s meaning.
At sea, Cam and James have a pact of silence against their father’s imperious bossiness. Cam doesn’t break it even as she’s tempted to give in to her father’s attempts to engage her, admiring him as she does.
Lily considers Paul and Minta’s failed marriage and her own singleness and wants to show the matchmaking Mrs. Ramsay how wrong her instincts were. Suddenly, Lily tears up at Mrs. Ramsay’s ghost and life’s senselessness. She looks for Mr. Ramsay’s sailboat, wanting to give him her sympathy.
At sea, James inwardly contrasts his father and mother. Cam feels spontaneously joyous and loves Mr. Ramsay.
On land, Lily observes how little one can know of other people’s lives and reminisces about the Ramsays. She reflects that the greatest skill is to see the world as simultaneously ordinary and miraculous.
At sea, Mr. Ramsay finally gives James the praise he craves, but James conceals his joy. Reaching shore, Mr. Ramsay leaps eagerly towards the Lighthouse.
On land, Lily and Mr. Carmichael agree Mr. Ramsay has reached the Lighthouse. Lily paints a final line and is satisfied, even knowing her painting will be forgotten. She has had her vision.