Jack drives eastward back to his life. He stops at a filling station in New Mexico, where he picks up an old man heading back to Arkansas. (The old man was driven to leave for California by the Dust Bowl, but discovered that California was no better than his home.) The old man has a facial twitch, of which he seems entirely unaware. Jack, thinking about the twitch, decides that it is a metaphor for the randomness and causelessness of life--the very ideas he had been soothing himself with in California, ideas which excused him from responsibility for Willie and Anne's affair--and begins to refer to the process of life as the "Great Twitch."
Feeling detached from the rest of the world because of his new "secret knowledge," as he calls the idea of the Great Twitch, Jack visits Willie and resumes his normal life. He sees Adam a few times and goes to watch him perform a prefrontal lobotomy on a schizophrenic patient, which seems to him another manifestation of the Great Twitch. One night, Anne calls Jack, and he meets her at an all-night drugstore; she tells him that a man named Hubert Coffee tried to offer Adam a bribe to throw the building contract for the new hospital to Gummy Larson. In a rage, Adam hit the man, threw him out, and wrote a letter resigning from his post as director of the hospital. Anne asks Jack to convince Adam to change his mind; Jack says that he will try, but that Adam is acting irrationally, and therefore may not listen to reason. He says he will tell Willie to bring charges against Hubert Coffee for the attempted bribe, which will convince Adam that Willie is not corrupt, at least when it comes to the hospital. Anne offers to testify, but Jack dissuades her--if she did testify, he says, her affair with Willie would become flagrantly and unpleasantly public. Jack asks Anne why she has given herself to Willie, and Anne replies that she loves Willie, and that she will marry him after he is elected to the Senate next year.
Willie agrees to bring the charges against Coffee, and Jack is able to persuade Adam to remain director of the hospital. That crisis is averted, but a more serious crisis arises when a man named Marvin Frey--a man, not coincidentally, from MacMurfee's district--accuses Tom Stark of having impregnated his daughter Sibyl. Then one of MacMurfee's men visits Willie and says that Marvin Frey wants Tom to marry his daughter--but that Frey will see reason if, say, Willie were to let MacMurfee win the Senate seat next year. Willie delays his answer, hoping to come up with a better solution. In the meantime, Jack goes to visit Lucy Stark at her sister's poultry farm, where he explains to her what has happened with Tom. Lucy is crestfallen, and says that Sibyl Frey's child is innocent of evil and innocent of politics, and deserves to be cared for.
Willie comes up with a shrewd solution for dealing with MacMurfee and Frey. Remembering that MacMurfee owes most of his current political clout, such as it is, to the fact that Judge Irwin supports him, Willie asks Jack if he was able to discover anything sordid in Judge Irwin's past. Jack says that he was, but he refuses to tell Willie what it is until he gives Judge Irwin the opportunity to look at the evidence and answer for himself.
Jack travels to Burden's Landing, where he goes for a swim and watches a young couple playing tennis, feeling a lump in his throat at his memories of Anne. He then goes to visit the judge, who is happy to see Jack, and who apologizes for being so angry the last time they spoke. Jack tells the judge what MacMurfee is trying to do and asks him to call MacMurfee off. The judge says that he refuses to become mixed up in the matter, and Jack is forced to ask him about the bribe and Mortimer Littlepaugh's suicide. The judge admits that he did take the bribe, and accepts responsibility for his actions, saying that he also did some good in his life. He refuses to give in to the blackmail attempt.
Jack goes back to his mother's house, where he hears a scream from upstairs. Running upstairs, he finds his mother sobbing insensibly, the phone receiver off the hook and on the floor. When she sees Jack she cries out that Jack has killed Judge Irwin--whom she refers to as Jack's father.