What is the main conflict in The River Between Us by Richard Peck?

This novel for young people is set within the historical context of the American Civil War. It tells the story of the unlikely friendship that develops between two white teenage girls, the sophisticated, Southern Delphine and the farm-living, Northern Tilly. As the narrative explores the social, personal and physical repercussions of both the war and of the two girls' very different values, it also explores issues relating to racism, the necessity for transcending prejudice, and the relationship between past and present.