Heart of Darkness centers around Marlow, an introspective sailor, and his journey up the Congo River to meet Kurtz, reputed to be an idealistic man of great abilities. Marlow takes a job as a riverboat captain with the Company, a Belgian concern organized to trade in the Congo. As he travels to Africa and then up the Congo, Marlow encounters widespread inefficiency and brutality in the Company's stations. The native inhabitants of the region have been forced into the Company's service, and they suffer terribly from overwork and ill treatment at the hands of the Company's agents. The cruelty and squalor of imperial enterprise contrasts sharply with the impassive and majestic jungle that surrounds the white man's settlements, making them appear to be tiny islands amidst a vast darkness. .
Marlow arrives at the Central Station, run by the general manager, an unwholesome, conspiratorial character. He finds that his steamship has been sunk and spends several months waiting for parts to repair it. His interest in Kurtz grows during this period. The manager and his favorite, the brickmaker, seem to fear Kurtz as a threat to their position. Kurtz is rumored to be ill, making the delays in repairing the ship all the more costly. Marlow eventually gets the parts he needs to repair his ship, and he and the manager set out with a few agents (whom Marlow calls pilgrims because of their strange habit of carrying long, wooden staves wherever they go) and a crew of cannibals on a long, difficult voyage up the river. The dense jungle and the oppressive silence make everyone aboard a little jumpy, and the occasional glimpse of a native village or the sound of drums work the pilgrims into a frenzy.
Marlow and his crew come across a hut with stacked firewood, together with a note saying that the wood is for them but that they should approach cautiously. Shortly after the steamer has taken on the firewood, it is surrounded by a dense fog.