This chapter begins with a return to Jack having to find 'dirt' on Judge Irwin. This will be his 'second excursion' into the past. The first one is about 'the story of Jack Burden' and when he was working on his American history PhD at State University. At this time, he shared an apartment with two men who he describes as alcoholics.
Jack describes himself at this time as hiding from the present. His research is based on Cass Mastern, a maternal uncle of his father Ellis Burden (the Scholarly Attorney). The majority of this chapter then relates the history of Cass Mastern and deviates from the main narrative.
Cass was born into poverty, but his elder brother Gilbert returned to the family home after making his fortune and assisted his brother by letting him manage a plantation. Following this, Gilbert sent him to Transylvania College. Here, Cass had an affair with Annabelle Trice and her husband Duncan committed suicide after finding out about it. It was thought to be an accident, but when Phebe (a slave of the Trices) finds Duncan's wedding ring under Annabelle's pillow it is clear that Duncan and now Phebe understand that Annabelle has been adulterous.
Annabelle sells Phebe because of guilt and the fear that Phebe will tell others of the true reason why Duncan died. Cass is greatly affected by this and believes that his one act (his affair with Annabelle) has led to consequences he never expected, such as the death of his friend and the betrayal of Phebe. He decides to find Phebe and set her free.
After searching fruitlessly for her, and being embroiled in a fight, Cass returns to working on his plantation. He frees his slaves and considers becoming involved in the Abolition movement. He tells a story of a former Abolitionist, Caroline Turner, who could not bear her slaves to look at her and so she flogged them mercilessly. Cass draws parallels with this, Annabelle's betrayal of Phebe and his sense of guilt with his freed slaves. Once these freed slaves leave for the North, Cass decides not to work this land with slaves again and so refuses to sell it.
With the outbreak of the Civil War, Cass joins the Mississippi Rifles and carries a weapon but decides he will not kill anyone as he has used up his right to blood. Whilst marching to war, he wears Duncan's wedding ring on a string around his neck. Finally, Cass is shot and 'rotted slowly to death' in a hospital in Atlanta.
As a student, Jack could not understand Cass. The present day, older Jack looks back at himself and sees that he could not grasp Cass's view of the world of responsibility, and the 'the world is one piece'. Cass's perspective of the world as a spider's web, where one act affects many others, are only words to Jack at this time. Jack reflects on hindsight that it is possible that he did understand Cass, but if so, he saw a reproach in Cass's sense of responsibility.
Jack turns away from his studies and enters on one of his periods of Great Sleep. He leaves the apartment eventually and the landlady sends him his parcel of Cass's papers. This unopened parcel travels with him from rooms to rooms and to the place he shares with his wife Lois.
This chapter is almost wholly devoted to Cass Mastern and his response to guilt. Superficially, this chapter appears to deviate too far from the concerns of Jack and Willie, but Jack's inability to engage with Cass's sense of guilt and self-reproach reveal how Jack has previously been unconcerned with moral responsibility. This inability is emphasized in Jack's initial lack of understanding with regard to Cass's spider web theory. Jack's lack of empathy and interest in only facts at this time is magnified in his inability to appreciate how one act (such as Cass having an affair with Annabelle) can have many repercussions, which is the point of the spider web analogy. However, it is possible to see a development in Jack when one compares his reaction to Cass as a student (when he turns away from his story) with his decision in the final chapter to complete his book about Cass.
It is also worth noting that Cass is the maternal uncle of Ellis Burden - the Scholarly Attorney - and is therefore nominally the great uncle of Jack. This chapter gives a greater shift away from Willie and fleshes out Jack's character and back-story. This means that Jack is far from being just a one-dimensional narrator. By giving the readers an insight into Jack's views of the world over a period of time, it is possible to recognize the changes he undergoes.