The Nellie, a cruising yawl, swung to her anchor without a flutter of the sails, and was at rest. The flood had made, the wind was nearly calm, and being bound down the river, the only thing for it was to come to and wait for the turn of the tide. The sea-reach of the Thames stretched before us like the beginning of an interminable waterway. In the offing the sea and the sky were welded together without a joint, and in the luminous space the tanned sails of the barges drifting up with the tide seemed to stand still in red clusters of canvas sharply peaked, with gleams of varnished sprits. A haze rested on the low shores that ran out to sea in vanishing flatness. The air was dark above Gravesend, and farther back still seemed condensed into a mournful gloom, brooding motionless over the biggest, and the greatest, town on earth.

船乗りマーロウはかつて、象牙交易で絶大な権力を握る人物クルツを救出するため、アフリカの奥地へ河を遡る旅に出た。募るクルツへの興味、森に潜む黒人たちとの遭遇、底知れぬ力を秘め沈黙する密林。ついに対面したクルツの最期の言葉と、そこでマーロウが発見した真実とは。