A black sharecropper's family is poor and hungry. The father and his dog, Sounder, go hunting each night, but the hunting is poor. The family subsists on biscuits and gravy until one morning they wake up to the smell of boiling ham. They eat it, but a while later a sheriff and two of his deputies burst into the cabin and arrest the father, saying that they have proof he stole the ham. Sounder runs after them, and one of the deputies shoots him.
The boy goes looking for Sounder but cannot find him anywhere. When he traces their steps, he finds blood on the ground along with Sounder's ear. He puts the ear under his pillow and wishes for Sounder's return. His mother thinks Sounder has gone off to die on his own, but for several weeks the boy goes in search of the dog each day. In father's absence, the family survives on the money mother makes by shelling walnuts. The boy undertakes the added responsibility of helping to look after his siblings, and he is stricken by the intense loneliness in the cabin.
Around Christmastime, the boy's mother makes a four-layer cake for him to bring to his father in jail. On the way there, the boy is nervous about being stopped and made fun of by the townspeople. When he arrives at the jail, the jail guard treats him rudely, making him wait to enter for a number of hours. Finally, the boy is let into the jail, and the guard breaks the cake into pieces. The boy gives it to his father anyway and tells his father that Sounder might not be dead. The conversation between the boy and his father is strained and awkward, and at the end of it his father tells him not to come back to the jail anymore.
The next morning the boy wakes up to the sound of faint whining and goes outside to find Sounder standing there. The dog can only use three of its legs and only has one ear and one eye. The boy and his mother tend to the dog, gradually getting used to the way Sounder looks. Soon they receive word that his father was convicted and sentenced to hard labor, traveling county to county. The boy resolves to search for his father, and, for a period of months, he journeys around the county looking for convicts working. One day the boy spots a group of convicts working, and he leans up against a fence to watch them, looking for his father. The guard watching the group whacks the boy on the fingers with a piece of iron and tells him to leave.
The boy runs to a school where he tries to wash the blood of off his hands. He finds an old book in a trashcan and carries it with him. While he is at the cistern, school lets out, and he eventually meets an old teacher who takes him in, dresses his wounds, and asks what has happened to him. The boy tells the teacher about Sounder and his father, and the teacher extends an offer for the boy to live with him and learn to read. The boy's mother tells him to go, and the boy stays with the teacher during the fall and winter, working in the fields during the summer. One fall the boy is at home helping with chores when they see his father walking back toward them. Half of his father's body is damaged from a dynamite blast, but the man has made it home.
The man and his dog are reunited and leave one night to go hunting. Sounder later comes back without his master, and, when the boy goes looking for his father, he finds him dead. Soon after, Sounder climbs under the porch and dies as well. Despite their deaths, there is a sense of peace and resolution over the family—especially over the boy, who has achieved the single thing he most wanted in the world, which is achieving his literacy.