The novel opens with a frame narrative in which an unnamed narrator and his friend Marlow meet Charles Powell, a retired sailor, at a riverside inn. Powell recalls the proudest day of his life: passing his seamanship examination and earning his certificate as a second mate. Weeks of fruitless job-hunting follow until a chance encounter leads him to the Senior Shipping Master at St Katherine's Dock House, just as Captain Roderick Anthony of the ship
Ferndale bursts in, desperate because his second mate has been hospitalized on the eve of departure. The Shipping Master presents young Powell as a candidate, and Anthony, mistakenly assuming the two Powells are related, hires him on the spot. Racing to the dock that night, Powell boards the
Ferndale and learns that the captain and his wife are sleeping aboard, an arrangement considered unusual and troublesome among sailors.
Marlow then takes over the narration, revealing his connection to the story through Anthony's sister, Mrs. Fyne, and her husband, John Fyne. Mrs. Fyne is the daughter of the late Carleon Anthony, a celebrated poet who was tyrannical in his own household. Her brother Roderick ran away to sea as a boy and became estranged from his father. Each summer, the Fynes host young women at their country cottage, where Mrs. Fyne mentors them in a fierce philosophy of feminine independence.
During one such summer, Marlow encounters one of these young women standing dangerously close to the edge of a hundred-foot quarry. He shouts a warning, and she retreats, but her dead-white face and wet eyelashes trouble him. Days later, the girl disappears. After a fruitless nighttime search, Fyne arrives the next morning with startling news: The girl has run off with Captain Anthony.
The girl is Flora de Barral, daughter of the notorious financier de Barral. Marlow recounts de Barral's career: a former clerk who seized on the word "Thrift" to advertise deposit schemes promising 10 percent interest with no coherent investment plan. His enterprises attracted enormous sums, but when the schemes collapsed, bankruptcy proceedings revealed the grotesque extent of his mismanagement. De Barral was sentenced to seven years' penal servitude.
Flora's childhood was blighted long before the crash. Her mother died of neglect at a country estate de Barral had bought sight unseen, and Flora was left under a governess who despised her. When de Barral's ruin struck, the governess unleashed years of suppressed hatred, calling Flora a fool and the daughter of a cheat. Flora fled and was caught by Fyne at his hotel. She was then handed over to a vulgar cousin of de Barral's, and months of humiliation followed. Later placements proved equally disastrous, and Flora reached the very end of her endurance.
It is at the Fynes' cottage that Flora meets Captain Anthony. He is visiting his sister for the first time in 15 years, shy and solitary. They meet accidentally on a road and begin walking together. Over several days, Anthony declares his love. Flora, unable to believe anyone could love her, resists, but his gentleness eventually overcomes her despair.
Mrs. Fyne, outraged by what she considers Flora's calculated entrapment of her brother, sends Fyne to London to confront Anthony. Marlow accompanies him to the Eastern Hotel. While Fyne is upstairs, Marlow encounters Flora outside and hears her account of the quarry: She had gone there intending to jump, but the frantic devotion of the Fynes' dog stopped her, and Marlow's shout broke her resolve entirely. Flora tells Marlow she has given Anthony "what he wanted, that's myself" and asks him never to reveal that he saw her at the quarry's edge. Fyne emerges shaken, reporting that Anthony was drafting his will leaving everything to Flora. Flora's overriding concern is her father's imminent release from prison; she has accepted Anthony partly to provide de Barral a refuge. Marlow watches Flora push through the hotel's glass door with the gesture of a sleepwalker and vanish inside.
Part II is told primarily through Powell's observations aboard the
Ferndale. Anthony and Flora marry at a Registry Office, but Anthony, tormented by Fyne's accusation of selfishness, establishes extraordinary terms for the marriage once they are aboard ship. He sleeps on a separate couch, has heavy curtains installed to divide the saloon, and tells Flora he will not approach her unless she gives him a sign. His scrupulous restraint leaves Flora unable to tell whether his distance is generosity or indifference.
De Barral, released from prison, arrives aboard the
Ferndale in a state of bitter resentment. He mutters "I am here under protest" and retreats to his state-room. In whispered conversations on deck, he tells Flora that Anthony is "getting tired of" her and urges her to make an escape. Flora, trapped between her father's obsessive possessiveness and Anthony's agonized withdrawal, maintains a mute, enduring silence.
Powell, the only young person aboard, befriends Flora during the watches and gradually senses something deeply wrong. The chief mate, Franklin, a devoted subordinate of Anthony's for six years, confides that the captain has become remote and silent, walking the deck as if in a trance.
On a moonless night, Powell stoops near a skylight at the ship's stern and discovers he can see through a clear glass pane into the saloon below. He watches Anthony pour a brandy-and-water and leave the room. A hand, old and puffy, reaches through the curtain, hovers over the glass, and withdraws. Powell rushes below and seizes the glass just as Anthony returns. Managing to whisper the word "Doctored," Powell mimes the poisoning gesture. Anthony grasps the situation and murmurs, "Not a word."
Flora emerges from her cabin, sensing the tension. Anthony, his resolve crumbling, tells her he is giving up and will let her go when they reach port. Flora cries out, "But I don't want to be let off," and flings her arms around his neck. De Barral, who has been listening behind the curtain, emerges ranting about conspiracies and treachery. In a sudden movement, he snatches up the poisoned glass, exclaims "Here's luck," and drinks. He collapses and dies. The true circumstances are never publicly revealed.
Powell remains with the Anthonys for nearly six years. Freed from de Barral's distorting presence, Anthony and Flora live at last as husband and wife. The
Ferndale is sunk in a collision with a Belgian liner in thick fog. Anthony ensures Flora reaches safety but goes down with his ship.
Years later, Marlow discovers that Powell has been sailing into an Essex creek near the village where Flora, now a tranquil widow, has settled. Marlow visits and finds her transformed. Flora confesses that she wrote Mrs. Fyne a reckless letter declaring she did not love Anthony; she discovered that love only through the agonies aboard the ship. She speaks of her years at sea with tenderness and mentions that Powell, her only real friend, visits often. When Marlow asks whether Powell might care for her, Flora replies, "Do you think it is possible that he should care for me?" The next evening, Marlow sails alone and sees two figures on the bank in the dusk. Powell calls out that he must see Mrs. Anthony home, and Marlow departs expecting happy news.