The Adventures of Tom Sawyer Chapter 10
Tom and Huck run back toward the village to the tannery, where they can hide. Once there, frightened of Injun Joe, they decided to swear an oath that they won't tell anyone what they just witnessed. Tom writes their oath on a piece of pine shingle, and then they prick their fingers and sign the shingle in blood. As they are doing this, someone sneaks into the tannery, but neither the boys nor the person notice each other.
After they sign the oath, they hear a stray dog howl--a sure sign that they will die. When they look, however, they see that its back is to them, meaning that someone else will die. They hear snoring and discover Muff Potter sleeping at the other end of the tannery. As they leave, the dog howls again, and they turn to see it facing Muff Potter.
Tom gets home and sneaks back in, not knowing that Sid is awake. The next morning he goes to breakfast, but Aunt Polly will not speak to him. After breakfast, Aunt Polly cries, telling Tom he breaks her heart with his misbehavior. Tom is overcome with guilt and also cries, begging for forgiveness and promising to be a better person. Aunt Polly dismisses him and Tom goes to school, unhappy. There he is beaten for playing hookey, but it does not affect him, sad as he is about hurting Aunt Polly. He sits down at his desk and discovers something wrapped in paper. It is his brass knob, which Becky has returned. "This final feather broke the camel's back." Chapter 10, pg. 70