- It is 8pm, and the action has moved to the rocks down on Sandymount Strand where Stephen stopped during his morning's walk in Episode 3, "Proteus."
- For the first half of the episode, a narrator describes the scene in sentimental prose, in the style of a romantic novel.
- Three girlfriends are seated on the rocks: Edy Boardman, who is there with her baby; Cissy Caffrey, who is there with her young brothers Tommy and Jacky; and Gerty Macdowell.
- Cissy Caffrey plays with Edy's baby, and Tommy and Jacky get into a fight over a sandcastle they are building.
- Cissy scolds Jacky for messing up Tommy's sandcastle, and tries to comfort Tommy. She guesses that he has to pee, and she has Edy take him around the way to do so.
- Gerty MacDowell is seated a bit away from the others, lost in thought. The narrator describes her beauty at length in hyperbolic (exaggerated) terms. He thinks that if she has been born in a different class, she could hold her own with any lady in the land.
- Gerty daydreams of a young man named Reggy Wylie, who has been riding his bicycle up and down outside of her window. She thinks of her prospects for the future, and how Edy makes light of the relationship.
- The narrator describes Gerty's dress at length, recounts how she coordinates her clothes and how she buys them. She wears blue pantyhose for luck.
- Gerty feels a burst of sorrow. The narrator describes how lovely she looks crying and how she will practice crying in front of the mirror. Gerty thinks that her fantasy over the Wylie boy will never come to fruition. She remembers her first kiss with him, where he pecked her on the nose. The narrator thinks whoever wins her, it will have to be a man among men, and she sits there waiting for her Prince Charming.
- Gerty sees Tommy Caffrey come out from behind the pushcar with Edy (where he was peeing). She thinks of how the other women will talk about her when she marries. Offhand, it is revealed that the citizen is her grandfather. She imagines how her husband will look, their honeymoon together, and how they will settle into a little house.
- Edy buttons up Tommy's pants. She tells him to play with Jacky, but he throws a tantrum because he wants to play with the ball with which Edy's baby is playing. Edy warns Cissy not to give in.
- Cissy teases the baby and gets the ball, which she tosses to Tommy. She says she'll do anything for a quiet life, and keeps playing with the baby so it'll forget about the ball.
- Edy says she'd like to get ahold of Tommy, and Cissy says she wants to hit him on the bottom. Gerty blushes at Cissy saying such an unladylike thing, and Edy scolds her and says a nearby gentleman (Bloom, who is down by the rocks a bit further down the Strand) probably heard. Cissy doesn't care.
- The narrator thinks of what a funny girl Cissy is, and recounts a time she dressed up as her father. He claims that she is sincerity itself.
- At the nearby Mary, Star of Sea Church, a temperance retreat begins with supplications to the Virgin Mary. Gerty thinks how sad it is that her father was a drunk. She claims to remember seeing him become violent in their house, and thinks that a man who hits a woman is the lowest of the low.
- Gerty recalls how her father used to go drinking with Paddy Dignam, and how he claimed that Dignam's death was a warning to him about his own habits.
- The narrator talks about what a good presence Gerty is in her household, like a second mother. Gerty thinks about the meaning of "halcyon days."
- Jacky and Tommy are playing happily with their ball, but then Jacky kicks it down toward the sea rocks. Bloom stops it and throws it to Cissy, but accidentally lands the ball right beside Gerty. Gerty tries to kick it but misses and Cissy and Edy laugh.
- Gerty raises her skirts a bit and gives the ball another big kick. She thinks that she raised them just to get the gentleman's attention, and notes that his face seems to be the saddest she has ever seen.
- The sounds of the temperance group imploring the Virgin Mary reach Gerty.
- The boys go back to playing happily, and Cissy plays with baby Boardman, trying to get him to say papa. She goes to sit him up straight, and realizes that he has peed all over himself. The baby laughs.
- Gerty is annoyed by the noise of the others. She thinks sentimentally of the beach scene, and notices that the dark man (again, Bloom) is looking at her intently. By his eyes, she guesses he is a foreigner, and begins to fantasize a romance between them. Her longing for Reggy Wylie begins to mix with a brief infatuation with the dark man.
- Gerty imagines the scene in the nearby church, and remembers a time she confessed to Father Conroy when he was very forgiving. She thinks of a present to get for him.
- The boys begin to quarrel again, and go running down toward the sea. Cissy is worried and goes running after them. Gerty sees that she lifts her skirt as she runs, and imagines she is doing it for the dark gentleman. She hopes that Cissy will trip and rip her skirt.
- Gerty listens to the sounds of the temperance group. She thinks that Cissy would have struck the children if she didn't think the gentleman was watching. Gerty thinks that Cissy is wrong; the gentleman is looking at Gerty, and she imagines what he thinks of her stockings.
- Cissy comes up with the twins, and Gerty takes off her hat so the man can see her hair. When she sees the intensity of his gaze, she thinks that she has raised the devil in him.
- Edy observes (roughly) what's going on, and asks what Gerty's thinking. She says she was just wondering if it was late. What she really wants to know is when Edy and Cissy will take all the kids home.
- Edy asks Cissy what time it is, and she says she'll go ask the dark gentleman.
- Bloom appears a bit nervous, and is playing with his watch-chain when she comes up. He tells her he thinks it is a bit after eight. Cissy comes back and says, "uncle said his waterworks were out of order" (13.64).
- The temperance group continues up the way. (Note the contrast between the religious group and one of the most explicitly sexual scenes in the book.)
- The man again fixes his gaze on Gerty, and she basks in it, knowing it is for her. She thinks that her menstrual cycle is coming on again.
- Edy asks Gerty if she is over the boy that threw her off, and Gerty is very hurt. She has to stifle a sob, and thinks that she loved Reggy more than he knew.
- But she replies in short order that she got over him quick as lightning and is ready to throw her cap at a new boy.
- Gerty thinks that Edy is jealous of her, and that Edy is angry that she appeared so strong.
- Edy gets up to go, and Cissy is playing with the baby. She pokes him in the stomach and he burps up on her. Gerty stifles a laugh, and draws attention to the benediction taking place in the temperance group.
- Gerty observes the scene and thinks about how the lamplighter will light the lamp outside her window where Reggy used to wait for her. She gets to thinking about poetry and how deeply it appeals to her, and then focuses, once again, on the dark man. She wonders what is bothering him so, and imagines their relationship together. She thinks that love can conquer all.
- As the sacrament is being put back in the tabernacle at the temperance gathering, Jacky sees that there are fireworks. Gerty and Edy and the children rush over to see them, but Gerty says she can see just fine from where she is sitting.
- She sees the man looking at her with whitehot passion, and suspects that he may be masturbating, but it doesn't bother her. She thinks this is somehow different because she can feel him focused upon her.
- Jacky sees a Roman Candle shoot up, and they all look up at it, and as Gerty looks up she lets her skirts rise, and Bloom climaxes, i.e. finishes masturbating. (Question: Why does the narrator wait so long to tell us this is Bloom?)
- Gerty looks over in his direction shyly, and Bloom instantly begins feeling ashamed, though he gets the sense that she will keep it a secret.
- Cissy cries to Gerty that they are all about to move on. Gerty gets up to go slowly, and tries to discreetly wave to Bloom with a handkerchief. As she moves over toward the group, Bloom realizes that she is lame in one foot.
- He feels bad, but is glad that he didn't realize it earlier. He is thankful that he didn't masturbate in the tub earlier because of Martha's letter, and then thinks of how women crave sex but they hide it better than men. He imagines that nuns are just vindictive for what they can't get. He thinks back to Martha and to Josie Breen, and remembers how they were sizing each other up in the street.
- Bloom thinks about Molly, and then about how the girl was actually attracted to him. He thinks perhaps it's because he didn't let her see him in profile. He thinks back on his ad in the paper, and wonders if he forgot to put the address on his letter to Martha.
- Bloom notes that his watch stopped at half past four, and thinks that it's done: Molly and Boylan have slept together by now.
- Bloom tucks his wet semen-covered shirt back into his trousers. He thinks what a mess masturbating makes, but that it's probably a necessity.
- Bloom remembers speaking to prostitutes in the street, and a previous sexual experience he had where the woman didn't know how to talk dirty to him.
- Bloom thinks about the different moments in a sexual encounter, how prostitutes enjoy taking a man from another woman.
- Bloom remembers how Molly told him her first kiss was with lieutenant Mulvey under the Moorish Wall. He thinks of other men that were attracted to Molly.
- He observes Cissy with the twins, and thinks how eager they must be to grow up. Bloom remembers another encounter with a prostitute.
- Bloom is a bit disappointed that Gerty never looked back as she was moving down the Strand. Bloom thinks that Gerty knew what he was doing, and thinks of how incredibly perceptive women are and how keen at getting the attentions of men.
- He thinks that the best place to put an ad for women would be by a mirror. He thinks of Milly before Molly's dressingtable when she was only three years old, and wonders whether or not the Mullingar character she is interested in is good enough for her.
- Another firework explodes, and Bloom considers what an incredible relief masturbating was after a stressful day. He wonders if some kind of language passed between Gerty and him.
- Bloom thinks of an Irish street ballad about a woman who swindles one man for another.
- He remembers that the ball he threw to Cissy rolled over to Gerty as if it understood. For a second, he considers the idea that Gerty is Martha Clifford.
- He wonders how Ms. Purefoy is doing at the hospital, and thinks of Dignam coming home drunk to his wife. Bloom imagines that you can always see a man's weak spot in his wife, but that men need some woman to take them in.
- Bloom has an unpleasant sensation in his loins, but when he fixes it he gets a pinch.
- Bloom notes again that his watch has stopped. He wonders if it is related to Molly and Boylan sleeping together, and begins thinking about the idea of magnetism. He thinks that it may be the same type of magnetism that takes place between men and women.
- Bloom imagines Molly in the sexual act, and considers that many women can't have an orgasm.
- He wonders why Gerty waved her handkerchief at him, and smells her perfume around him, which is not too different from Molly's own scent. He thinks that perfume is like a veil for women, and considers how Molly's smell permeates everything in their house.
- Bloom wonders what a man smells like. He thinks that priests don't have it, and imagines women begging priests for their first time.
- He pokes his nose inside his jacket, and smells the lemon soap. He remembers that he forgot to pick up Molly's lotion and pay for his soap, and he wonders if it will stop the grocer from extending credit to him in the future.
- A nobleman passes by Bloom, and he considers following him like the newsboys followed him earlier in the day. Bloom imagines writing a prize story about the mystery man on the beach, and then thinks about how one can feel the atmosphere in one's body.
- Bloom sees the light house down at Howth's Head, and considers how light is reassuring. He thinks about the science of light and colors.
- Bloom thinks again about Gerty and other women that he has been attracted to throughout his life. He remembers being with Molly on Howth's Head, and thinks that Boylan is with her now: "he gets the plums and I the plumstones" (13.108).
- Bloom feels tired and drained. He thinks about being old, and how there is "nothing new under the sun" (13.109). He remembers playing games with Molly when they were younger.
- Bloom thinks he sees a bat, and wonders if it thinks he will turn into a tree through metempsychosis. The temperance mass comes to an end, and he sees the lights go on in the priest's house. Bloom thinks that the repetition in a mass is a good idea, and is not too different from repetition in advertising.
- Bloom thinks again about how light relates to color, and tries to remember who learned to concentrate sunlight through a magnifying glass. He remembers that it's Archimedes.
- Bloom thinks about the migratory life of flying animals, which gets him thinking about sailors, and he thinks about how hard it must be for their wives when they leave. He considers the fact that sailors' superstitions may be justified because their lives are so uncertain, and wonders if fish ever get seasick.
- Bloom takes a survey of the scene. Another firework shoots up, and we learn that it is for the Mirus charity bazaar for Mercer's hospital (where the viceregal cavalcade was headed in "The Wandering Rocks"). The postman goes door to door, and a boy goes around lighting lamps, and another goes around announcing the results of the Gold Cup race. He thinks that the light from an anchored ship is winking at him.
- Bloom recalls going for a pleasure cruise with Molly and Milly. He thinks how odd it is that children don't fear death, but are afraid of being lost when their mother disappears for two seconds. He thinks of kid's playing battle, and wonders how they can point (fake) guns at one another.
- He thinks of Milly counting his waistcoat buttons as a child, and how he could learn so much about her when he took her hand. He remembers her crying for him when she had growing pains, and how scared she was when she had her first period.
- Bloom thinks that Milly's first period must have made Molly think of her youth. He thinks of Molly's other suitors, and wonders why she picked him.
- Bloom considers heading home. He thinks he will call to see if Mina Purefoy is still laid up in the hospital. He considers all that he's been through today, and wonders if he was wrong to shout back at the citizen. He thinks how funny it is that all the men in bars are afraid to go home and be alone, like children.
- He thinks again of Dignam, and thinks of the widow collecting insurance. He thinks of how sad widowers look, and then of how no woman ever thinks she is ugly. He thinks of Dennis Breen wondering about, and remembers that he has to nail that ad for Keyes and get some petticoats for Molly.
- Bloom picks up a piece of paper on the beach that he thinks is from an old copybook. He again thinks of how exhausted he is.
- He considers waiting for Gerty the next day, and then picks up a stick and begins scratching a note to her in the sand. He writes, "I AM A" before deciding that there's not enough room on the beach (13.119-121). He brushes the words away with his boot.
- He thinks, "Hopeless thing sand. Nothing grows in it. All fades" (13.123).
- He tosses his stick into the sand and it sticks up right. He wonders what the chances are.
- Bloom decides he will take a short nap, and as he dozes off he thinks of elaborate goodbyes to Gerty, and thinks to himself in sentimental child-talk about what happened.
- As he drifts off a cuckoo clock sounds from the priest's house, and he wonders if Gerty MacDowell thinks that he is "Cuckoo Cuckoo Cuckoo" (13.129).