After I read Half of a Yellow Sun, I saw a few reviews that compared Adichie to Chinua Achebe (including the back of this novel). I read Things Fall Apart in high school, so I had a hard time seeing the connection (partially due to lack of familiarity with Achebe, partially due to an inability to remember the novel very well). I actually thought that comparison was more obvious and accurate in this novel. It appears to take place in the '90s after a military coup (I checked Wikipedia first, and then found this site to confirm my suspicions - she writes of the death of a reporter in the novel and I had assumed that was the real name -Nwankiti Ogechi - but even that was fictionalized). The coup served as a backdrop to the rest of the novel, which focused on a much more personal story.
As the story progresses, the narrator, Kambili, begins to question her upbringing, and become more independent. In the beginning, she worships her strict father. We soon learn that her father is not only strict, but abusive and fanatically religious. His beatings have induced miscarriages upon his wife, and he is quick to punish his family for what he sees as wrong-doings (for example, he beats his wife for having to be asked more than once to go into the minister's house when she was feeling naseuous). He is intolerant of different beliefs and has even cut off contact to his father because his father holds on to the old religion. His children have a daily schedule and are expected to be first in their class - he doesn't care that his controlling all their time leaves them no time to develop friendships, and actually earns them ridicule as "snobs." Kambili and her brother Jaja visit their liberal aunt's family, and through interacting with these relatives, they begin to question their own lives and enjoy themselves and new freedoms.