Gale has slowly turned on Rosalean, who was saved only within seconds from becoming one of them. She is angry with him for abandoning her, but he only did what he did because he thought she was out of control.
She was the competitive gymnast who felt like no one loved her. He was the baseball player who had loved her for a while. When these two high school seniors get together, life changes in ways they never would have expected.
I suck at summaries, so don't judge the story based on this.