Philip Stolz is a seaman who spends the night cheating on his wife and boards the vessel he's been assigned to just in time. As the days on the ship pass, he settles into his sea routine and acknowledges to himself that his affections for his wife have cooled. However, his mind is then preoccupied by a new passenger that he loathes: the syphilitic engineer Bradley Holliday, whose every mannerism seems contemptible to Stolz. Despite this hatred, there are times that Holliday slips up and reveals his true character, with which Stolz finds himself sympathizing. Reluctantly, he agrees when Holliday invites himself over to the radio room to 'talk,' feeling as though it might be impossible to refuse. Holliday arrives carrying liquor and letters from his fiancée. He shows Stolz a photograph of the woman, Phyllis, and begins to read the love letters she sent him. Stolz is deeply uncomfortable with having private letters read aloud like this, but his protestations are all too easily silenced. The two men get progressively more drunk as Phyllis's personality is dissected and examined rather cruelly through her prose. Stolz sees in her the false intellectuality that his own wife assumes to establish her superiority over him, and he is filled with conflicting emotions: his loathing of her and his conviction that in some twisted way, they are two sides of the same coin. It becomes clear to Stolz that Holliday is simply carrying out this grotesque charade because he wants someone else to tell him what to do with this girl, especially because of his sickness and the demands of his job - and Stolz is trapped in the terrible certainty of knowing that her life as a married woman, no matter who the husband is, will be miserable. When Holliday leaves, Stolz finds that one of the radio batteries is dead. He goes out on the deck to discard it only to find Holliday throwing Phyllis's letters and photos into the sea. He is filled with rage, having come to think of Holliday's fiancée as 'our mistress,' and nearly kills the man, raising the heavy battery and preparing to bring it down forcefully - but Holliday turns at the last moment, and the two men stare at each other as the sun rises.