What is the main conflict in Blood Rites by Jim Butcher?

Blood Rites by Jim Butcher, the sixth book in The Dresden Files, focuses on the battle between Harry Dresden and the Black Court vampires. The foes that Harry faces are formidable but things are complicated when Harry discovers that he has a half brother who is a member of the White Court vampires. The power of love becomes a central theme for the story as Harry is forced to face his past and realize that his future will be changed forever.