Anna has four notebooks: one black, one red, one yellow, and one blue. In the black notebook, the pages are divided down the middle by a black line. The left side of the line reads "source"; the right side reads "money." The left side is about Anna's novel Frontiers of War, and the right is about transactions, money she received from it. Anna first talks about meeting various people wanting to make a screen adaptation of the novel. She does not like their plans for the novel, and she feels that her work has been misunderstood. After its publication in 1951, her novel became a bestseller. The novel tells the story of Peter, a young English pilot who is deployed to Africa during World War II and eventually has an affair with a Black woman.
Anna drifts into recounting the events and people that inspired Frontiers of War. She was a part of a Communist sub-group in the African colony of Rhodesia (now Zimbabwe); in 1939, she has moved to Rhodesia with a man named Steven. The relationship ends quickly, but Anna finds herself unwilling to return to England, so she lingers while working as a secretary. She begins a relationship with a German man named Willi Rodde, and this relationship leads her to stay in Africa, becoming involved in leftist politics. It also leads her to make the acquaintance of a group of young men who are pilots in the Royal Air Force: Paul, Jimmy, and Ted. Paul was cold, calculating, and wealthy; he was killed in an accident right before he was supposed to leave Africa. Jimmy is inclined to be melancholy, partially due to his repressed homosexuality. Ted is always fixated on intellectual projects and is the most politically committed of the group. Maryrose, a young woman who has grown up in the colony, also becomes a member of this group of friends, as does George Hounslow, a local working man.
On a whim, the group visits the Mashopi Hotel, which is run by a couple named Mr. and Mrs. Boothby. They have an adolescent daughter named June. Anna and her friends come to spend a lot of time at the Mashopi Hotel over the coming months, often debating politics and how best to organize the local community in service of their political agenda. Their community gradually expands, including Stanley Lett, a young man whom Ted is striving to educate, and Mrs. Lattimer, a woman who stays at the hotel. As the group becomes closer, George eventually confides that he has been having an affair with an African woman who is the wife of Mrs. Boothby's cook, and that his mistress has given birth to his child. Meanwhile, Stanley begins an affair with Mrs. Lattimer.
The various sexual and emotional tensions come to a head one weekend when a big dance is held at the Mashopi. Mrs. Boothby has been growing increasingly frustrated with her cook, Jackson, who has formed a friendship with Paul, and rebukes him several times. Mrs. Boothby finally fires Jackson, and when Anna expresses her frustration, Willi suggests it would be for the best for George to be forcefully separated from the cook's family. Annoyed, Anna slips off with Paul, and the two of them end up making love. When they return to the hotel, Mr. Lattimer is berating his wife, presumably because he knows of her affair. Anna doesn't hide her actions from Willi, and their relationship effectively ends. The next morning, Jackson and his family have left. The rest of the group disbands as well: Paul is killed a few days later, while Jimmy is deployed. Anna notes that these events were the inspiration for her novel.
With the frame narrative of Anna's present-day life in 1957 London in place, the narrative takes us back in time to explain a previous chapter in her life and the inspiration for her novel. The frame narrative had already established Anna as a somewhat unconventional woman who lives life on her own terms, but as readers learn about her time in Africa, they realize that she has been involved in some radical choices. The description of her time in Africa highlights a period where a close-knit group challenged both political and sexual conventions. While the Mashopi Group apparently formed based on political beliefs, it is significant that Anna writes in her notebook mostly about the sexual and romantic tensions that animated the group.
In European cultural imaginations, colonies were often presented as places with greater freedom and sexual license. In practice, power dynamics and the fact that individuals might be separated from their families and communities did mean that people might live more openly outside of England. In the first section of the novel, Molly had described how traveling outside of England allowed her to feel freer, as though she did not need to conform to social norms. In Rhodesia, various characters embody sexual license. Anna and Willi openly pursue a relationship without needing to be married, while George has a long-term extramarital and biracial relationship. Homosexuality is also hinted at as something that was more permissible, although also still controversial. Some of the dangers and problems of the Mashopi Group seem to stem from characters taking this atmosphere of license too far and forgetting that they do not exist entirely outside of social expectations. Anna's interest in exploring this atmosphere of sexual and romantic freedom is reflected in her novel focusing on a biracial relationship, which would have been very controversial in the 1950s.
Alongside sexual and romantic experimentation, this section also highlights Anna's attention to how power dynamics intersected with class and race, along with questions of imperialism and militarism. Though it seems like the group is free to experiment and work to create social change, they are still operating within a geopolitical framework of imperialism and war. All of the RAF pilots are training to engage in highly dangerous combat and are keenly aware that they might lose their lives at war. This threat is ironic because their personal values (free love, homosexuality, etc.) and political ones (i.e. Communism) put them significantly at odds with traditional British values, but these young men are still putting their lives at risk. Paul's death in a futile and preventable accident challenges the value of militarism. The setting of the military conflict within a colonial backdrop also highlights political hypocrisy: British soldiers are being trained to fight and die to protect and liberate people from Hitler's armies, but black Africans are themselves not treated as fully equal or entitled to political rights.
The events of the Mashopi Group plotline reach a kind of climax when unspoken and tacit secrets come to the surface. This process mirrors what Anna will experience throughout the novel: one of the central struggles is for her to access her unconscious and be honest and transparent about what she is actually feeling and thinking. While the Mashopi Hotel is a space of relative freedom, it also ends up functioning as a microcosm of social and domestic society where the keeping of secrets is what allows people to function together. Various people are turning blind eyes to illicit relationship and sexual tensions, and when these come to the surface, the fragile bonds holding the group together end up crumbling.