The summer ten-year-old Opal and her father move to Naomi, Florida, is the same summer Opal adopts Winn-Dixie, the scrappy dog abandoned in the town grocery store. Her canine pal, with a lively spirit matching its new owner, accompanies Opal as she meets new people. One afternoon Winn-Dixie wanders off, and Opal finds her dog snacking on peanut butter at the house of the woman deemed a witch by Opal's bothersome playmates. To her surprise, this "witch" is actually Gloria Dump who has wrinkly old skin and wears a big floppy hat adorned with printed flowers. In their regular visits, Opal reads Gone with the Wind to Gloria, whose eyes have weakened with age, and tells her about her latest adventures. In turn, this "witch" acts as a mother-figure to Opal, teaching her about being tolerant of others and their mistakes.
Opal also befriends the very wealthy librarian Miss Franny Block, who shares great stories about her past, including a tale about her great-grandfather, whose family members died while he fought for the South in the Civil War. Grief-stricken after his return from battle, he decided he wanted to live the remainder of his life filled with sweetness. Thus, he invented Littmus Lozenge candies that tasted like a combination of rootbeer and strawberry with a secret ingredient mixed in -- sorrow. In Because of Winn-Dixie, these candies symbolize that even though life sometimes deals people a bit of sadness, there is always so much to appreciate.
This lesson initially escapes Opal, as she bemoans the loss of her mother. But over time, Opal makes new friends, and her days become increasingly sweet. She finds charm in quiet Otis, a former jailbird and now pet-shop worker whose lyrical music touches all of the animals in the shop. She reaches out to the pinch-faced Amanda who has experienced a deep tragedy at a young age. And she learns to tolerate the bothersome Dewberry brothers who tease her (as many boys do when they have fond feelings toward a girl).
Enveloped by the security that her new community brings, Opal finally appreciates life's treasures and begins to accept that her mother is never coming back. By the end of Because of Winn-Dixie, Opal truly understands Gloria has been telling her all along: "...[Y]ou can't hold on to anything. ...[Y]ou can only love what you've got while you've got it." The spirit of DiCamillo's delightful story about Opal echoes long after the last page has been read.