The Castle is a surreal unfinished novel about the struggles of a land surveyor named K who reports to a village surrounding the titular structure. K attempts to perform his duties, but the various bureaucrats living inside the castle thwart and alienate him repeatedly until his life becomes a grueling circuit of red tape and contradictory statements. K becomes ill later in the book and the story's planned ending involved his death without the resolution of his quest.
The protagonist, K., arrives in a village governed by a mysterious bureaucracy operating in a nearby castle. When seeking shelter at the town inn, he claims to be a land surveyor summoned by the castle authorities. He is quickly notified that his castle contact is an official named Klamm, who, in an introductory note, informs K. he will report to the Mayor.
The Mayor informs K. that through a mix-up in communication between the castle and the village he was erroneously requested. But the Mayor offers him a position as a caretaker in service of the school teacher. Meanwhile, K., unfamiliar with the customs, bureaucracy and processes of the village, continues to attempt to reach Klamm, which is considered a strong taboo to the villagers.
The villagers hold the officials and the castle in the high regard, even though they do not appear to know what the officials do. The actions of the officials are never explained. The villagers provide assumptions and justification for the officials' actions through lengthy monologues. Everyone appears to have an explanation for the officials' actions, but they often contradict themselves and there is no attempt to hide the ambiguity. Instead, villagers praise it as another action or feature of an official.
One of the more obvious contradictions between the "official word" and the village conception is the dissertation by the secretary Erlanger on Frieda's required return to service as a barmaid. K. is the only villager that knows that the request is being forced by the castle (even though Frieda may be the genesis), with no consideration of the inhabitants of the village.
The castle is the ultimate bureaucracy with copious paperwork that the bureaucracy maintains is "flawless". But the flawlessness is a lie; it is a flaw in the paperwork that has brought K. to the village. There are other failures of the system: K. witnesses a servant destroying paperwork when he cannot determine who the recipient should be.
The castle's occupants appear to be all adult men, and there is little reference to the castle other than to its bureaucratic functions. The two notable exceptions are a fire brigade and that Otto Brunswick's wife declares herself to be from the castle. The latter declaration builds the importance of Hans, Otto's son, in K.'s eyes as a way to gain access to the castle officials.
The officials have one or more secretaries that do their work in their village. Although they sometimes come to the village, they do not interact with the villagers unless they need female companionship, implied to be sexual in nature.