A group of men were on an English ship on the Thames. The group included a lawyer, an accountant, a company director and a man without a specific profession whose name was Marlow, the narrator seemed to be a component of the crew too. Marlow started to talk about London and Europe as the darkest place on earth and began the story of how he entered into the dark continent. No one seemed paticularly interested, but he continued anyway.
Marlow, the protagonist and mani narrator of the story had the desire to explore the uncharted areas of the world, especially that of the center of Africa. His Aunt, who had connections with the Company, was able to recommend Marlow as captain of a steamboat. The previous captain, Freslaven, died during a fight with the natives and Marlow replaced him. Marlow travelled to Africa and arrived in the Outer Station, where he met the chief accountant, a man who lived in the continent for three years, but he kept himself clean and well-dressed yet. Marlow learnt from him the existence of a certain Mr. Kurtz, a well known agent and the best ivory-trader in the Company . Marlow saw the terrible condition and treatment of the African natives.
The general manager, informed Marlow that his steamer had sunk to the bottom of the river. Having heard this, Marlow decided to rescue the steamer and fixing it up. One day, a grass shed at the station went up in flames, and a native was beaten supposedly for starting the fire. When the native recovered, he went away through the woods. Later, while Marlow was in the brickmaker's quarters, he noticed a somber painting of a blindfolded woman holding a torch. The brickmaker revealed that the painting was done by Mr. Kurtz
Marlow continued on the river on his steamboat with a crew of several whites, about 20 to 30 blacks, and a few cannibals. As he travelled down the river, he came across an abandoned shack where he collected wood, and a note cautioning him to travel carefully. Then he got surrounded by savages in the fog. Marlow was frightened but the savages didn't do anything... until the fog rose. The savages attacked and Marlow's men had a tight without them. Only Marlow's helmsman died. Marlow blew the whistle and mysteriously, all the savages retreated in fear.
Marlow shortly reached the Inner Station, where he was greeted by the Russian Trader, a man who seemed to survive in the heart of the continent by not knowing what was going on around him. Kurtz was very ill and had to be taken back to England, but he did not went to go. In fact, he ordered the attack on the steamboat so that they couldn't take him back to England. Kurtz is worshipped by the natives and completely exploited them. That night, Kurtz tried to escape to the natives but Marlow caught him and takes him back to the steamboat to head back for England. While still on the river, Kurtz died saying, "The horror, the horror." Marlow returned to England. He visited Kurtz's Intended who was still in mourning a year after Kurtz's death. She still remembered Kurtz as the great man he had been before he left, and Marlow didn't tell her what he had become before he died. He told her that Kurtz's last words were her name. Marlow gave her the old letters and left her.