What is the plot of the story?

Dad and Momma, as the Watson children call their parents, are determined to raise respectful, well-behaved children who make good choices and possess high moral standards. Realizing they have been unable to instill fully their standards in their oldest child, Dad and Momma decide to take By to Birmingham and leave him with his Grandma Sands, a strong woman who will bring him to his senses. They know there is some violence in the South with the beginnings of the Civil Rights Movement, but have been assured by Grandma Sands that it is quiet around her.

In Birmingham, Grandma Sands meets them with arms open wide and a home filled with love for her daughter and family. By's only recollection of Grandma Sands is when he was four years old, and he has convinced Kenny and their kindergarten sister, Joetta, that she is a mean old woman. Kenny and Joetta have never met her prior to their visit in the summer of 1963, and By's description of Grandma Sands has scared Kenny. Kenny and By both take her measure and decide By can easily take this mean old woman down.

Kenny and his family have gone to Birmingham just as the violence moves into Grandma Sands neighborhood. First, Kenny nearly drowns and By saves him, then the nearby Baptist Church is bombed on Sunday morning. In the remainder of the story, Kenny must deal with his emotions that are tangled up with the "Wool Pooh" he meets first in his near drowning experience and then a second time in the bombed church.