The Metamorphosis by Franz Kafka

Gregor Samsa awakes one morning in his family's apartment to find himself inexplicably transformed overnight into a gigantic insect. Gregor does not immediately recoil from his insect form, but instead chooses to lament his job by saying, "How am I going to get to work?" and the general misery of the rainy weather outside. Indeed, the narrative establishes the poor conditions as the cause of his bed-ridden state. Gregor works as a traveling salesman, and, as it is usual for traveling salesmen to move constantly from place to place, he is accustomed to waking up in unfamiliar surroundings and various circumstances. The true reality of his metamorphosis is complete when he sees his many legs waving in the air. But from then on he resists any conscious recognition regarding his change or the fact that a change indeed happened—everything but the recognition of his separation from the others. The problem Gregor has at the beginning of the story is that his family and a messenger from his boss are knocking at the door, concerned for him, and he's unable to flip off his back onto the floor.
The weight on Gregor’s life is that he is the financial head of the household; nobody else apparently works in his family (or is able to work); their whole present and comfortable existence relies upon Gregor’s employment at the "firm." Most of the weight is the debt which his father owes to the employer for whom Gregor now works.
Gregor is unable to speak in his insect form, and never successfully communicates with his family at all after his physical appearance is revealed to them. He is alienated by being suffered the usage of a voice of some other thing. However, he seems to retain his cognitive faculties, which are unknown to his family.
Curiously, his condition does not arouse a sense of surprise or incredulity in the eyes of his family, who merely despise it as an indication of impending burden. However, most of the story revolves around his interactions with his family, with whom he lives, and their shock, denial, and repulsion whenever he reveals his physical condition. Horrified by his appearance, they take to shutting Gregor into his room, but do try to care for him by providing him with food and water. Grete, the sister, takes charge of caring for Gregor, initially working hard to make him comfortable. Nevertheless, they seem to want as little to do with him as possible. Grete and the mother shrink back whenever he reveals himself, and Gregor's father pelts him with apples when he emerges from his room one day. One of the apples becomes embedded in his back, causing an infection.
Time passes while he is confined to his room. Gregor's only activities are looking out of his window and crawling up the walls and on the ceiling. Financial hardship befalls the family, and Grete's caretaking deteriorates. Gregor’s perception diminishes throughout the course of the story. It is apparent that Gregor’s physical size is getting smaller and smaller (small enough to cover a picture frame), and so too the size of his personal identity seems to shrink. Due to his infection and his hunger, he is no longer able to crawl up the walls and is soon barely able to move at all.
Aside from being an untouchable entity in his new state, Gregor decides to hide underneath a sheet when somebody has to come into his room. As much as he tries to imprison himself within his room, his family become the jailers, locking Gregor in from the outside. Devoid of human contact, Gregor alternates between concern for his family and anger at them for neglecting him. One day Gregor emerges to the sound of his sister's violin with the hope of getting his much-loved sister to join him in his room and play her violin for him. He has a fantasy about him telling Grete that he plans to send her to the conservatory to study violin. But her rejection of him is total when she says to the family, We must try to get rid of it. We've done everything humanly possible to take care of it and to put up with it, no one can reproach us in the slightest.
The sister then determines with finality that the insect is no longer Gregor, since Gregor would have left them out of love and taken their burden away. Gregor returns to his room and collapses, finally succumbing to his wound and to his self-induced starvation.
The point of view shifts as, upon discovery of his corpse, the family feels an enormous burden has been lifted from them, and start planning for the future again. Fantastically, the family suddenly discovers that they aren't doing badly at all, both socially and financially, and the brief process of forgetting Gregor and shutting him from their lives is quickly accomplished. The final sentence echoes the first: while the opening lines document Gregor's physical metamorphosis, the novella ends with mention that Grete too has changed, having become a "good looking, shapely" girl who will soon be old enough to marry.