Joseph Conrad, Heart of Darkness

The novella centres on the efforts of Marlow, Conrad's alter ego, to travel up an unnamed African river on behalf of his employer in order to bring back a rogue ivory trader, Mr Kurtz. Kurtz's reputation precedes him: "He is a prodigy... an emissary of pity and science and progress." Yet as Marlow gets closer to Kurtz, there is the growing suggestion that he has in some way become corrupted and descended into savagery. The further upstream Marlow gets, the more intense the sense of impending danger, with cryptic warnings and a bloody ambush ratcheting up the tension. When Marlow finally reaches Kurtz's camp, he discovers a scene of unimaginable depravity. The dying Kurtz is taken aboard the boat (along with a prodigious quantity of ivory), but he does not survive the journey back downstream. With Marlow present, his chilling last words are "The horror! The horror!"