What significant challenge does Fiona face in the novel, The Folks That Live on the Hill?

Fiona's challenge can be found is her destructive self-image. She sees herself as an alcoholic, and as if to prove that she is, she goes about drinking constantly.

Years earlier, a relative had asserted that she was the perfect image of another relative, who had killed herself with alcoholism. Fiona took this to heart, believing herself to be physically addicted to alcohol and doomed like her supposed model.

She nearly dies, but Harry finds proof that the two women looked nothing alike. He shows Fiona that she was wrong; she is not exactly like her alcoholic relative. At the novel's end she is undergoing a transformation; her behavior is changing as she forms a new self-image.