Ten-year-old India Opal Buloni has just moved to the fictional small town of Naomi, Florida with her father who is a preacher.While at Winn-Dixie, Opal encounters a scruffy Berger Picard that is wreaking havoc. She (not wanting the manager to send him to the pound) claims that he is her dog and names him "Winn-Dixie". He becomes friends with everyone he encounters, and so Opal makes some new friends in the process. She also rekindles her relationship with her father and learns ten things about her mother, Benjean-Megan, who abandoned them when she was three. She describes the preacher as a turtle, always sticking his head into his shell, and never wanting to come out into the real world. This is most likely because of how sad he is about her mother, whom he is still in love with.One of the people Opal meets is Miss Franny Block, a kind and somewhat eccentric elder librarian, who tells her many great stories, including one involving a bear who invaded the library. She also meets Gloria Dump, a blind African-American recovering alcoholic with a "mistake tree" with beer bottles hanging from it in her backyard. She tells Opal that the bottles, including alcohol bottles, represent the ghosts of all the things she has done wrong.One day, fed up with Winn-Dixie, the landlord of the Bulonis' trailer park, Mr. Alfred, demands they get rid of him. The preacher calls the pound, but Opal begs to keep him. Unable to see her upset, he asks the pound to return Winn-Dixie, claiming he is not the same dog he called about. The preacher is able to convince Mr. Alfred to allow them three months' time to find Winn-Dixie a new home. However, it is later revealed that, like a lot of the characters, Mr. Alfred is dealing with difficult feelings which impact how he interacts with the Bulonis and Winn-Dixie.Opal gets a job at Gertrude's Pets and befriends the manager Otis, a shy ex-convict with a passion for music. She also meets a young girl named Sweetie Pie Thomas, who is eager to get a dog like Winn-Dixie. With enough new friends, Opal and Gloria decide to host a party. Opal also takes a risk by inviting Mr. Alfred to the party as well, which he, after hesitating, begrudgingly accepts. Opal also becomes a friend to her former enemies, the brothers Stevie and Dunlap Dewberry, and to her sour-faced neighbor, Amanda Wilkinson, who lost her younger brother Carson when he drowned in the town lake the previous summer, which inspires Opal's compassion.During the party, a severe thunderstorm strikes, and Winn-Dixie, being pathologically afraid of them, runs away. While Opal looks for him, her father wants to give up and she blames him for the loss of her mother and Winn-Dixie running away. He explains that he tried very hard to look for her mother. He then admits that it was his fault that she left him, and he believes that she is never coming back. However, he is grateful that she left Opal with him. Later they go back to the party and Otis starts to play a song on his guitar. Winn-Dixie is heard outside howling along to it. Everyone, while singing, lets him in and welcomes him back.