What is the main conflict in The Underground Gardens by T. Coraghessan Boyle?

The story is loosely based on the life of an Italian American immigrant who began digging a huge underground complex on his land in Fresno, California, in the aridSan Joaquin Valley, in the early 1900s. Using this historical person and elements of his life as a start, Boyle crafts an optimistic story about an Italian American immigrant whose hopes— including marrying the woman of his dreams—are repeatedly dashed, but who nevertheless perseveres and continues to dream.