Obi is granted two weeks of local leave so that he may go and see his father about the "urgent" business he had written his son a letter about. Before Obi leaves, Clara helps him collect his things and pack, and the night before he departs she attempts to break off the engagement once again. Obi blames himself, saying that he understands that she does not want to be married to someone who cannot manage his finances. She says that she does not want to come between him and his family and that she does not want to ruin his life. The end of their argument persuades Clara against breaking off of the engagement.
Obi leaves early the next morning. He will only spend one out of the two weeks leave in Umuofia because he does not have enough money to stay longer. People will expect him to pay for things, to invite and offer, because of his large salary, and they will not understand that someone with his position in the civil service cannot afford this. Thus, he decides to only stay one week.
When he arrives in Umuofia at his home, he asks for his mother and discovers that she is very ill. She has just returned from the hospital within the last week and looks very badly to Obi who is extremely saddened by his mother's illness and appearance. At the end of the chapter there are singing women who pass by to sing for them, which is against Obi's father's will, since the women have just sung at a funeral.
Obi has a conversation with his father about Clara. His father is opposed to his marriage to this woman, but Obi uses the ideas of Christianity to defend his position. He claims that with Christ there is no bondage and no judgment of the sort his father is committing and that just because their ancestors had made mistakes in the past does not mean that they have to continue to make those same mistakes, even after having been shown the "light" of the Gospel.
Obi's father is almost convinced. The next morning, however, Obi sees his mother about the same issue. His mother gives him an ultimatum that he does not have the strength to defy. Hannah, Obi's mother, says that he must wait until she is dead if he wishes to marry such a woman as Clara and that if he does not wait, she shall commit suicide. Obi is troubled by this very much and is unable to find the strength and conviction to challenge his mother, which is the most troubling thought of all for Obi.
Obi decides that he will leave early and has a final conversation with his father before he leaves. Obi's father tells him of the curse his own father placed on him when he left his house in search of Christianity, and it is with this tale that the chapter ends.
Up until now Achebe has created many chapters in opposition or juxtaposition to one another in order to illustrate the kind of life that Obi lives and has lived through the literary device of parallels and opposites. At this point in the novel, however, everything seems to take on a linear structure as the novel travels through the ends of Obi's recent past.
In chapter 13 there is quite a bit of foreboding. First, Clara begins to cry again because she believes she will ruin Obi's life and cause him family strife, which indeed she does, through no real fault of her own. Then, Obi's mother is quite ill and, at the end of the chapter, there are women who come to sing for her. However, the women that come to sing for her are the singers who have just come from a funeral. Achebe has them stop by the house as if to foreshadow Obi's mother's own death. Also, the song that they sing is relevant to Obi's own dénouement. The lyrics to the song go as follows: "For a kinsman cannot be bought in the market, / Neither is a brother bought with money." This verse exists to remind the reader of Obi's eventual "selling" of himself proving this verse wrong.
Also, it is important that this is the first time in the novel that Obi cannot find enough strength within him to stand up with conviction for what he believes. He has lost his will in many ways and does not want to have his mother's blood on his head. The story about the razor blade that caught his mother's hand begins to take on a different meaning here. The blood is no longer a bond but a threat.
Finally, there are the conversations that Obi has with his father. It is important to realize that Obi uses the language of Christianity and the language of "enlightenment" (the same language he had used to criticize the colonialists) in order to convince his father that his marriage to Clara is not something that is wrong. He, like Achebe, knows how to use the tools, the language, and the culture of the outsider, of the colonizer, to his advantage.
At the end, Obi's father understands and provides a parallel of his own: he tells the story of when he leaves his house with a curse upon his head for wanting to be a Christian. This is very much like the way Obi is being treated for wanting to marry an osu. It is almost as if Obi's father has given in and almost as if he understands. However, he claims that it is because of all of this trouble that he truly knows and understands what Christianity means. Perhaps then, Obi's father is not only telling him that he, in some way, understands, but also that he must truly understand what he is doing. Yet, Obi seems to have the conviction to fight his father, but his conviction to fight his mother is weak and dying.