Evelina opens her letter by confessing she has a volume to write about a single opera night that unraveled every social safeguard she possessed. While she and Maria Mirvan dress for Haymarket, the Branghton sisters burst into the chamber, treat her prior engagement as pride, and leave offended after she explains that pit dress at the opera matches the boxes. Their parting threat that Madame Duval will rage proves immediate: Duval storms the Mirvans in scarlet fury, orders Evelina to obey, and the Captain's Ranelagh mockery turns the quarrel into public warfare until Mrs. Mirvan warns that further resistance will mean a total breach. Evelina yields, follows Duval into a hackney coach, and watches the Captain's grinning servant earn a slap in the street.
At Duval's lodgings the whole Branghton clan waits in the passage, quarreling over coach fares and examining Evelina's pit finery as if she were a spectacle. Duval refuses to let her borrow a hat, so she enters the opera house conspicuously overdressed for the company she keeps. Mr. Branghton does not know half-guinea pit tickets admit one person each; he fumbles his guinea at door after door until the party lands in the one-shilling gallery, which they mistake for a cheat until the curtain rises. They compare Italian singing to Drury Lane, talk through Signor Millico, and mock Evelina when she leans forward to listen; from the front row she sees Lord Orville seated by Mrs. Mirvan below while Sir Clement searches the gallery and eventually spots her head-dress.
Humiliated by the prospect of cousin familiarity before Willoughby, Evelina accepts his offer to conduct her downstairs, tells Duval she will join Mrs. Mirvan to spare the coach, and slips away before the Branghtons can speak. The plan collapses at once: Mrs. Mirvan has already gone home, and Lord Orville, leaving the pit, exclaims in shock to find Evelina alone with Sir Clement. Orville offers his coach and servants with delicate courtesy; Willoughby interrupts, orders his chariot, and hands Evelina in before she can recover a witness or a chair.
The ride becomes predation dressed as rescue. Willoughby grasps her hand, declares love, and admits he has sought privacy away from Captain Mirvan; when she demands speed, the coachman seems to wander until she tries to leap from the moving chariot and calls aloud for him to stop. He kneels for forgiveness, extracts a promise not to tell the Mirvans, and only then reaches Queen Ann Street, where Miss Mirvan meets her at the door and Lord Orville stands waiting inside. Evelina colours at Sir Clement's false tale about Piccadilly while Orville politely rejoices at her safety; she spends the night fearing he believes she chose Willoughby's company, even as Miss Mirvan reports Orville's anxious impatience for her return. The letter closes with Tuesday's departure from London and dread of dining with Duval today.
