The story opens with the narrator recounting a summer sea voyage from aboard the ship 'Independence'. The narrator learns that his old college friend Cornelius Wyatt is aboard with his wife and two sisters, though he has reserved three state-rooms. After conjecturing the extra room was for a servant or extra baggage, he learns his friend has brought on board an oblong pine box: "It was about six feet in length by two and a half in breadth." The narrator notes its peculiar shape and especially an odd odor coming from it. Even so, he presumes his friend has acquired an especially valuable copy of 'The Last Supper'. The box, the narrator is surprised to learn, shares the state-room with Wyatt and his wife, while the second room is shared by the two sisters. However, for several nights, the narrator witnesses his friend's surprisingly unattractive wife leaving the state-room every night around 11 o'clock and going into the third state-room before returning first thing in the morning. While she is gone, the narrator believes he hears his friend opening the box and sobbing, which he attributes to "artistic enthusiasm." As the ship is caught in a terrible hurricane an escape from the damaged ship is made via a lifeboat, but Wyatt refuses to part with the box and issues an emotional plea but is denied by Captain Hardy. Wyatt decides he cannot part with the box and returns to the ship, ties himself to it with a rope...