The book begins with the image of the father standing on the porch, petting Sounder. The boy, his son, asks the man how he got Sounder, and the father explains that Sounder came to him on the road as a pup. The boy loves Sounder, especially now that he does not go to school. The walk is too far—eight miles each way—and, in the winter, is much too cold. The boy thinks about what a great hunting dog Sounder is and how the dog could shake a possum dead from a tree without even puncturing its skin. Perhaps the most impressive quality about the dog is its bark, which echoes so loudly, even musically, that most of the neighbors can hear it.
The father tells the boy that if it is not too windy, they will go hunting that night. They go inside where the boy's mother is cooking corn mush for dinner. They all eat together, including the three younger children. The boy's father and mother talk about how the hunting will be better next year, and the boy thinks of all the empty sacks with which his father and Sounder have been coming home. It is windy after dinner, so the boy feeds Sounder and then his father leaves to hunt by himself. The boy's mother spends the night shelling kernels of walnuts for extra money. The boy wishes she would sing or tell a story to help abate the "night loneliness" he feels. The boy can hear Sounder underneath the porch and wonders where his father went alone.
The boy dreams that, just as in the Bible, there is a flood and all the houses are floating on water. When he wakes up, he smells ham bone, which is something he has only smelled twice in his life. The boy notices that his mother is humming, which happens usually when she is worried. They eat the ham, and, after breakfast, his mother mends a tear in his father's overalls. At night the boy is lonely and vows to learn to read so "he wouldn't be lonesome even if his mother didn't sing."
A few days later the family is still eating from the ham bone. Around dusk they hear footsteps, and three white men enter the cabin. One says, "There are two things I can smell a mile One's a ham cookin' and the other's a thievin nigger." One of the men grabs the tablecloth, which is soaked in grease, and the other man points out the rip in the father's overalls, saying that it happened when the father stole the ham. The men take the boy's father, and Sounder begins to follow them, barking. They threaten to shoot the dog if he does not stop. The boy tries to hold Sounder back and succeeds until the men are down the road. Finally, Sounder rips away from the boy and runs after the wagon. The deputy shoots him, and Sounder falls down on the road.
The boy runs after Sounder. The dog tries to get up but cannot. The side of his head and shoulder is missing. His mother beckons for his return and tells him to leave the dog to die in peace. Later the boy goes to look for Sounder, but the dog is gone. The boy finds Sounder's ear on the ground and takes it with him, putting it under his pillow so he can wish for Sounder to live. Before the boy goes to bed, he fills Sounder's food dish and leaves it outside, just in case.
One of the first noticeable aspects of this book is the fact that no one except Sounder has a name. The protagonist is simply "the boy," and his parents are "the boy's mother" and "the boy's father." The lack of names immediately suggests that these could be any people, anywhere. They are not particularly special or important, and they are not particularly anything. Armstrong wants the reader to perceive these people as average, even slightly below average. They are poor, nineteenth-century African Americans who cannot read and who live a meager existence. Armstrong chooses this cast of characters for a number of reasons: first, not many books are written about black sharecroppers such as these, especially in 1969. Perhaps the Civil Rights Movement inspired such a story. Second, these are characters whose inability to change is profound and disturbing. They have little money and little opportunity, and it is easy for their lives and characters to remain stagnant. Third, Armstrong depicts how difficult daily life is for these people, even on the good or easier days. Sounder is the only being to have a name in the entire book, and perhaps that is meant to underscore the fact that many African-American sharecroppers had no real identity during this time period. Sounder has more of an identity than they do, which illuminates an ironic and horrible reality.