What is the main conflict in Lilith's Brood by Octavia E. Butler?

Lilith's Brood by Octavia E. Butler is the story of how Humanity was saved from the war it waged on itself by an alien species. The aliens, known as the Oankali, are nothing like Humans and while they revere life, they believe that to let Humans alone, only to destroy themselves again, is the same as allowing death. The story focuses on the Human resisters who want their freedom returned, regardless of the consequences, and the lives of the Oankali and Humans that are trying to work together.