The key theme of continuity and change in this excellent tale is communicated principally by the protagonist, Michael Obi, and his wife, Nancy. Note their attitude about the backward school that they hope to reinvigorate by the force of their personalities. They accept this job because they want an opportunity to bring this school and its village into the modern world, as they see it still being trapped in primitive and superstitious ways. This of course introduces us to the massive conflict between new European ways that are imposed upon native indigenous cultural norms.
The way in which an old woman "trespasses" on school property on her way back from a native shrine, even though she is just walking on a sacred footpath, brings this conflict into the open. Michael Obi, as the character representing change and forward thinking, therefore pits himself against the various forces of tradition and continuity that are ranged against him and will not embrace the new modern ways he espouses as easily as he thinks they will. Therefore we can see this theme is focused on through plot, character and setting in this text.