As 4:00pm approaches, two bar staff at the Ormond Hotel watch the viceregal cavalcade pass by. Lydia Douce and Mina Kennedy chat about the soldiers and then scold an “impertinent” (247) busboy. Outside, Bloom walks past. Simon enters the bar, followed by Lenehan, who claims that he is searching for Blazes Boylan. As they serve drinks, the bar staff talks about a young, blind piano tuner, who tuned the piano “for the smoking concert” (252). Simon plays a few notes to test the man’s work. When Boylan arrives, he flirts with Mina and then waits with Lenehan to hear which horse won the Gold Cup. Bloom notices that Boylan has parked his car outside. He knows that Boylan is scheduled to meet Molly at 4:00pm, so he decides to follow Boylan. He reaches the Ormond Hotel and, outside, he meets Richie Goulding. Bloom agrees to eat dinner in the bar with Goulding, hoping that he will be able to watch over Boylan from his table. Inside, Boylan and Lenehan prepare to leave. As they exit, they walk by Ben Dollard and Bob Cowley. Bloom and Goulding order drinks from the waiter, Pat. When Bloom hears Boylan’s car drive away, he is nearly overwhelmed with sadness and anxiety. On the other side of the bar, Simon talks to Dollard about music. Dollard remembers borrowing clothes from secondhand clothing shop run by the Bloom family for one performance. Simon and Dollard both praise Molly, who “saved the situation” (257). Bloom is also thinking about his wife as his dinner is served. As Pat brings the food, the narrative is interrupted to describe Boylan’s journey to meet Molly.

When Dollard sings, Bloom recognizes the song as Love and War. He remembers when Dollard borrowed clothes from Molly’s store. Simon is encouraged to sing an opera song, which makes Goulding reminisce about opera concerts. Bloom discusses Goulding; he sympathizes with Goulding’s back troubles but dislikes his frequent lies. Goulding praises Simon’s singing. Bloom blames alcohol for hindering Simon’s singing career. Since Simon’s song is from an opera called Martha, Bloom thinks about coincidences. He was just about to write to Martha. Instead, he remembers the first time he met Molly. The patrons applaud Simon’s song as Tom Kernan enters the bar. Thinking still about the song, Bloom wonders how Simon fell out with Goulding. The song’s lyrics make him reflect on death and Dignam’s funeral. Music, Bloom decides, has a mathematical dimension. Despite her talents, Bloom believes that Molly has poor taste in music. He composes his letter to Martha, hiding his writing beneath a newspaper and telling Goulding that he is simply responding to a newspaper advert. His words are flirtatious, and he inserts a half-crown coin in the envelope. Despite this, he feels bored by Martha. A gentle tapping sound—eventually revealed to be the blind piano tuner’s cane—is heard. Bloom watches the bar staff flirting with the customers as the patrons sing opera songs. To Bloom, music seems to be everywhere in the world, from the voices of women to the inherent sexuality of acoustic music. He cannot stop thinking about the rendezvous between Molly and Boylan. Meanwhile at Bloom’s house, Boylan knocks on the door.

Kernan asks Dollard to sing the Irish nationalist song—The Croppy Boy—which he was thinking about in Episode 10. The subject of the song is an Irish nationalist who, following the 1798 rebellion, is executed by a British man who had disguised himself as a priest. To Goulding’s disappointment, Bloom begins to leave. He waits quietly to listen to the end of Dollard’s song and stares at Lydia, wondering whether she sees him. The song makes Bloom reflect on the status of his own family. He begins to sexually fantasize about “charming” (270) Lydia but then snaps out of his reverie and bids farewell to Goulding. Bloom exits the bar just as the “most trenchant rendition of that ballad” (275) ends and the patrons burst into applause. Feeling the effects of the alcohol, Bloom walks to the post office. He is annoyed that he scheduled a meeting with Cunningham for 5:00pm to discuss Dignam’s insurance. He continues to think about Dollard’s song. Back at the Ormond Hotel, Simon is told that Bloom has just left. The men talk about Bloom and his wife’s “fine voice” (277) as the piano tuner arrives to collect his forgotten tuning fork. Outside, Bloom spots a local sex worker named Bridie Kelly. He once paid to have sex with her and now cannot look her in the eye. Instead, he stares through a shop window at a picture of Robert Emmet, a “gallant pictured hero” (278) and Irish nationalist whose famous last words are inscribed in the shop window. Bloom reads the words to himself while breaking wind due to the gassy alcohol he consumed in the bar. The sound of a passing tram saves him from embarrassment.

Episode 12 introduces the first-person perspective of an unnamed narrator. At the same time, the story is interrupted by allusions to Irish culture and literature such as folklore, mythology, newspaper articles, bureaucracy, and the law. The unnamed narrator meets Joe Hynes while walking on the street. They go for a drink in Barney Kiernan’s pub, where Hynes talks about “the foot and mouth disease” (281). In the pub, they meet the citizen, who is described in an elaborate, mythological manner. The citizen has a “mangy mongrel” (283) named Garyowen. When “that bloody old pantaloon Denis Breen in his bath slippers” (286) and his wife pass by the pub, Alf Bergan tells a mocking story about Breen’s postcard and then orders a pint of Guinness which is described in glowing terms. The citizen sees Bloom pacing up and down on the street and disapproves. He believes that Bloom is a “bloody freemason” (288). The people in the bar discuss Dignam, including a séance that apparently summoned the dead man’s soul. Bob Doran (who appeared in Joyce’s short story collection Dubliners) mourns Dignam’s untimely death, though the narrator notes that Doran seems to be swept up in his annual bout of alcoholism. When Bloom enters the pub to meet Cunningham, he declines Hynes’s offer of a drink. When the patrons discuss “capital punishment” (292), Bloom offers his pedantic opinion. The citizen leads the discussion by talking about Irish nationalists who were hanged by the British. While the citizen talks, the narrator observes Bloom and thinks about Molly. He knows the Bloom family well through Pisser Burke. Bloom tries to explain a point but the citizen interrupts, speaking broadly about nationalism. Hynes orders more beer as the narrator scornfully judges Bloom for not drinking with the other men. Bloom fumbles through a conversation about insurance, explaining that he plans to meet Cunningham and then visit Dignam’s widow with regard to “this insurance policy of poor Dignam’s” (300).

When the conversation turns to the Dublin mayoral race, the citizen criticizes one of the frontrunners—Nannetti—for being Italian. The men discuss sports, and the citizen is praised by Hynes for “the Gaelic sports revival” (303). Bergan talks about boxing, mentioning that Boylan won money on the fight. Bloom tries to change the subject to “lawn tennis and the circulation of the blood” (305), but the men continue to talk about Boylan, who hatched a devilish scheme to win money at a boxing match. Bergan mentions that Boylan and Molly’s concert tour will begin soon. When Bloom becomes quiet, the narrator assumes that Molly is having an affair with Boylan. Ned Lambert and J. J. O’Molloy enter the bar. The men discuss Denis Breen and his mental health and legal struggles. Bloom alone sympathizes with Denis’s wife as the men discuss “scandalous” (309) legal cases. During a conversation about Irish politics, the citizen turns to Bloom and makes antisemitic statements about “strangers in our house” (310). Bloom pays him no attention. Lenehan and Nolan enter, talking about the Gold Cup. The winner was “a rank outsider” (312) named Throwaway, meaning most of the men lost their bets. The citizen continues to talk loudly about politics and the British colonization of Ireland. He wishes that Ireland could respond with force to British imperialism. Bloom counters, suggesting that Irish nationalism will only create a cycle of violence. The citizen and Nolan criticize Bloom, suggesting that he is not really Irish. Bloom defends his nationality, claiming that a nation is “the same people living in the same place” (317). The other drinkers laugh at him; the citizen spits in the corner. Bloom believes in life and “universal love” (319) rather than hatred and violence. Then, he leaves momentarily in search of Cunningham and the citizen mocks his pacifist tendencies.

Cunningham arrives with Crofton and Power. When Cunningham asks after Bloom, the men gossip about Bloom. Cunningham says that Bloom’s family are historically from Hungary. Their original family name was Virag, he says. The citizen mocks Bloom, referring to him as “the new Messiah for Ireland” (323) and claiming that his children were fathered by another man. He mocks Bloom for being “feminine.” Cunningham defends Bloom and raises his glass to the other patrons. Bloom returns, unaware that the other men believe that he has won a large sum of money betting on Throwaway. They are annoyed that he has not used his winning to “stand us a drink” (326). As the room seems to be seething with an anger that is about to spill over, Cunningham escorts Bloom out of the pub with Power and Crofton. They go to Cunningham’s car as the citizen chases them out into the street, shouting antisemitic remarks at Bloom. The citizen’s actions disgust the narrator. Bloom is angry. As Power holds him back, he shouts a list of famous Jewish men at the citizen. The list includes Jesus Christ. The citizen hurls a cookie tin at the car, which hits the vehicle. In a passage that resembles a Bible verse, Bloom in the car is compared to Elijah ascending to heaven in a chariot.