Gustav von Aschenbach is introduced as an older famous author out for a walk in his hometown, Munich. As the clouds darken and a storm approaches, he encounters a red-haired man glaring at him, rousing a longing to travel to a place opposite to that where he resides. He believes the journey will improve his writing.
The controlled childhood past of Gustav von Aschenbach led him to follow his parents' ideals and become well-known before he had the ability to experience the stages of growing up. He is depicted as having a weakened immunity yet able to battle through it as have the main characters in his novels.
His adventure begins with a trip to the rainy Adriatic island, which does not suit Aschenbach's yearning for a wondrous new getaway, causing him to sail for Venice a few days after. On board the ship he experiences spells of dizziness as he watches those around him, in particular a group of men which appear to be young, but after close examination Aschenbach realizes one of them has used make-up, dentures, and a wig to conceal his age. When he arrives at his destination, which is again a disappointing darkness contrary to the sunlight he was expecting, this same old man drunkenly attempts to allure Aschenbach. Aschenbach transfers to a gondola headed in a suspicious direction by a criminal who later on disappears, and he likened the gondola to a coffin. Once at the hotel, Aschenbach notices a beautiful adolescent Polish boy during dinner, likened to Eros, the Greek god of love. He sees him again the next morning, later watching him play on the beach, and again riding the elevator. He discovers his name to be Tadeusz, and up close he is sighted as seeming ill, which causes Aschenbach to secretly relish in the idea of the boy dying early. Due to unfortunate weather conditions, Aschenbach decides to leave yet again, and sends off his luggage; after missing the train, he discovers his luggage was misplaced and therefore must stay in Venice a few days more. He sees the boy through his window and is delighted at having more time to spy on Tadeusz.
Aschenbach receives his missing luggage, but chooses to stay and analyze every beautiful piece of Tadzeusz, giving him daydreams of Socrates pursuing his student Phaedrus. This seemingly parallels his own situation, as Socrates is unattractive and elderly, while Phaedrus embodies youth and beauty. After this he delighted himself in writing about Tadzeusz's body, later almost making contact with him at the beach. As he is overcome with his obsession, he metaphorically describes the surrounding nature as Greek gods, Tadzeusz being Hyacinthus. As he watches the boy, they lock eyes and Tadzeusz gives him a smile, to which Aschenbach realizes his love for the child.
Signs of an epidemic appear as the public are warned to avoid the water and shellfish, less and fewer people, and German newspaper. Secretly, Aschenbach wishes for a quarantine so he may have more time fantasizing and stalking Tadeusz. He defends his obsession by depicting it as art. The Venetians, specifically a red-headed musician Aschenbach asks, attempt to conceal the fact that an epidemic is happening by stating the bactericide is being used only as a precaution, relating to his own obsession as he attempts to conceal it as well. At a British agency, Aschenbach discovers the epidemic is cholera, coming from India. The thought of leaving is soon dismissed by the fantasy of Tadeusz with him in quarantine. At night, he has dreams of humans in beast skins worshipping a Dionysian and perverted representation in a wooden statue, which are metaphorically himself worshipping his desires. When the cholera is uncovered, tourists leave, Aschenbach takes the opportunity to attract the boy by transforming into a figure mentioned earlier (the old man on the boat attempting to look youthful with make-up and a wig), relishing in the idea of everyone else dying and leaving only Tadeusz. Aschenbach masticates on rotten strawberries as he walks down the littered streets until he reaches the beach to watch Tadeusz playing rough with his friend. When the boy notices him, he smiles and points outward. Aschenbach, however, cannot rise to meet him, and dies.