Bobby didn't mean to get all the girls mad at him and the rest of the boys, it was just that the girls were so different all of a sudden, even his best friend, Holly.
Bobby's looking forward to fourth grade. He'll be in the same class with all his friends, including Holly, who's been his best friend since kindergarten, even if they didn't act like it at school. Holly even gave him Rover, the goldfish she'd won at the amusement park, because he'd loaned her the dollar she spent winning him.
But Bobby knows things are going to be different when Holly wears a dress on the first day of school, and started walking home with stuck up Jillian, instead of walking with him, like they'd always done. And then Bobby begins to realize that when he's around Holly, things just seem to go wrong, no matter how much he wanted them to go right. Then one day, Bobby finds out that Holly's told Jillian some of his secrets, secrets he'd never told to anyone else. He can't believe it — that's not the way a real best friend acts!
Bobby does a lot of things that year. He teaches Rover to do tricks. e gives his father advice on how to make his brown bag lunches for school. He hugs a lonely looking tree that hugs him back. He eats his dad's cookies that taste like burned library paste. And he starts a war, a boys and girls war. Fourth grade turns out to be a very interesting year, after all!