The book tells the story of a man who wakes up one morning to find himself transformed into a giant insect. His transformation causes him to lose his job and become ostracized from his family, who are horrified and repulsed by his new form. As he grapples with his new reality, he becomes increasingly isolated and starts to lose his sense of humanity. The book explores themes of alienation, guilt, and identity, and is a profound examination of the human condition.