John, the narrator, asks to be called Jonah. He begins the novel with an introduction to the Hoenikker family and the religion of Bokononism. Although Jonah began his life as a Christian, he is now a devoted Bokononist. The Hoenikkers are not Bokononists, but Jonah states that they are members of his "karass." Jonah emphasizes the inability of humans to understand what God is doing and why he is doing it, a fact that is underscored by Jonah's inability to know the true limits of his "karass" group or its total membership. The instrument through which each karass fulfills God's will is called a "kan-kan," and Jonah's planned novel titled The Day the World Ended is the kan-kan through which Jonah was first connected with the Hoenikkers.
Jonah's book is going to chronicle what important Americans did on the day the atomic bomb was dropped on Hiroshima. While he is gathering facts for this work, he runs across a newspaper published by Cornell University's Delta Upsilon fraternity, an organization to which he belonged when he was a student. The publication lists Newt Hoenikker as one of the new pledges for the chapter, and Jonah recognizes him as the son of physicist and Nobel Prize winner Felix Hoenikker. Because Felix Hoenikker was one of the leading scientists behind the development of the atomic bomb, Jonah contacts Newt in an attempt to obtain anecdotes about life in Felix's house the day the bomb was dropped.
Newt's response to Jonah's letter indicates that Newt was only six years old on the day in question. Newt reports that he was playing with toy trucks in his home in Ilium, New York, and his father was in his study fiddling with a loop of string. His father often stayed home from the Research Laboratory of the General Forge and Foundry Company where he worked so he could putter around his Ilium home or his cottage on Cape Cod. Newt notes that his father usually had no fondness for made-up games or tricks because he was more interested in the natural riddles and diversions in the world. Felix hardly ever took interest in books or people, including his own family. Nonetheless, on the day the bomb was dropped, Felix was playing with this string and inadvertently twisted it into a "cat's cradle" configuration. Newt remembers this as the first and only time that his father tried to play with him, and he remembers that Felix left his study and thrust the cat's cradle into his young son's face. Felix attempted to show Newt all of the parts of the cat's cradle, encouraging him to imagine the string as an actual bed for a cat. Newt, however, was distracted by the smell of cigar smoke on his father's clothes and by Felix's frighteningly large pores, ears, and nose. The sight was so startling that Newt burst into tears and ran out of the house. Angela, Newt's sister, was twenty-two years old at the time. She later told Newt that his reaction hurt his father's feelings, but Newt doubts that he hurt his father deeply, since Felix had almost no interest in people. (As a side note, Newt notes a time when he asked his father about Emily Hoenikker, Felix's wife, who had died giving birth to Newt. His father could not remember anything about her.)
When he ran away from his father, Newt found his brother Frank Hoenikker in some bushes outside of their house making bugs fight in a jar. He sat with his brother until Angela came looking for him. When she found him in the bush, Newt was still traumatized and kept repeating how much he hated Felix and how ugly he was. Angela slapped Newt and insisted that their father was one of the greatest men who ever lived. In his letter, Newt attributes Angela's loyalty to the fact that their father was all that she had. Back then she did not have any friends or boyfriends, and her only hobby was playing the clarinet. Angela kept slapping Newt until Frank punched her in the stomach so hard that she fell into the grass crying. She called for their father, but he only stuck his head out of one of the house's windows briefly before returning to his study. People, including his own children, were not Felix's specialty.
Newt finishes his letter with a series of postscripts to clarify its contents. First, he indicates that because of his grades he has flunked out of the medical school at Cornell. Newt also informs Jonah that he is a midget and that his brother Frank is wanted by the Florida police, the FBI, and the Treasury Department for running stolen cars to Cuba. Finally, Newt mentions that he does not want to give the impression that all he does is pity himself, and he expresses his happiness that he is currently engaged to a woman whom he loves. This woman is a Ukrainian midget named Zinka.
Zinka presents herself to the Russian Embassy two weeks after Newt's letter. She wants to return home because she thinks Americans are too materialistic. After Zinka's departure, Newt retreats to his sister's home in Indianapolis.
Jonah's preferred name indicates how he thinks of himself in relation to the story he will tell. He says that he chose the name Jonah because he feels as though somebody compels him to be in certain places at certain times. Jonah is also the name of a prophet in the Bible who is compelled to do God's will despite his attempts to disobey. Throughout the novel, Jonah is amazed by the ways in which the seemingly random events in his life seem to be leading him to some inescapable fate. This idea is central to Bokononism, which holds that humans cannot understand God's plan but are unable to resist his will.
The first chapters of the novel introduce the "karass," which is a group called together to do God's will. It is clear from Jonah's writings that the karass is the most important relationship one person can have with another, and he contrasts this kind of relationship with the "granfalloon," a proud but meaningless association of human beings. Newt and Jonah share two granfalloons: their university and their fraternity. Such relationships are comforting, but they also mislead individuals regarding where their loyalties should lie with respect to their destinies and their lives' works.
In Jonah's letter to Newt, he refers to Newt as "Brother," as is the custom of individuals who belong to the same fraternal organization. Newt's reply mentions that he is being kicked out of school and his fraternity because of his grades, so he can no longer call Jonah his brother. Thus Vonnegut comments on the superficial and sometimes nonsensical relationships that individuals force themselves into and which can prevent them from sharing meaningful relationships. In doing so, individuals' granfalloons distract them from the real work of their karasses and ultimately lead people to cause some of the world's more serious problems. Participation in granfalloons can convince a person to fight on behalf of one's family, state, or country, but indirectly; in the grand scheme of things the individual's membership in granfalloons is merely accidental or superficial. Newt's relationship with Jonah is an example of such a superficial relationship, because it is easily ended by Newt's inability to do well in school. When they belonged to the same fraternity, Jonah considered Newt his brother, presumably making them closer than they otherwise would be. This presumption is justified because as soon as Newt is kicked out of school, they no longer have a relationship as brothers, although there was no real change in their relationship as individuals. Superficial social identities have little staying power.
Vonnegut's depiction of Felix Hoenikker is also an introduction to one of the book's overarching themes, the role of deception in making a distinction between right and wrong. Felix, while intelligent enough to be one of the world's greatest scientists, had no concern for or knowledge of the human beings he interacted with every day. He spent very little time with his own children and showed a general indifference to their existence and that of his wife. He viewed his wife, and later his daughter, as caretakers. It is unclear at this point in the novel whether he loved his family or even understood the concept of love, but his failure to show that emotion aids in the portrayal of Felix as the unfeeling scientist who delights in solving tricks and puzzles to the detriment of humanity.
When a scientist commented to Felix that the atomic bomb was the first meeting of science and sin, he responded, "What is sin?" This response shows Felix's relative moral innocence; as a scientist, Felix has never encountered or internalized a concept of morality. Meanwhile, his research had moral implications. The creation of the atomic bomb, while a huge advance for science, was also a moral danger because it dramatically increased the scale of destruction that a nation could inflict on another in a short period of time. Felix's lack of moral responsibility creates a chilling portrayal of scientists who not only express the absentminded qualities of the inventor but who also work with minimal regard for human life. This lack of concern for the plight of others is paralleled, to a lesser extent, in the lives of Newt and Frank. Frank shows no concern for the bugs that he is pitting against each other when Newt finds him outside, and he instead concentrates on his interest in the game of making them fight. Also Newt, in his letter to Jonah, briefly mentions two girls who committed suicide by jumping into a gorge by which he was planning on taking a walk. He seems uninterested in their demise except to relate the surprising fact that they committed suicide because they did not get into the sorority (another granfalloon) they had wanted to enter. There is no sense of sorrow or remorse for these individuals. The unfeeling, unjust lack of concern for other members of humanity will be a repeated theme as Vonnegut's novel progresses.