Why is Thomas glad to be working at the same farm as Charlie?

Bertha begins to come up missing. She will be gone for a while, then come home, or even worse, be found in the woods, lost and confused. One day, she does not come home. Thomas, Big Joe, and his mother all set off to find her. Thomas is just about to give up and go home when he hears a gun shot. When Thomas gets to the old shed in the woods that his father used, he sees the Colonel with his shotgun and Bertha dead at his feet.