I think the book will be about "Protection."
Statement: You need to trust someone who can protect you or your family
*Katniss: Katniss protected Prim from the danger going into the hunger games so she wouldn't have to go, and she volunteered as a tribute.
*Gale: Gale had said that he would try his best to keep Katniss' Mom and Prim safe while she was gone.
*The Baker: He told Katniss that he would watch out for her mom and Prim,but mostly to Prim and would provide them with a bit of food from the bakery.