Dewey is a sparrowman residing in the Winter Woods with a western accent. He is a widely known fairy and the keeper of all fairy knowledge, giving him his famous nickname "The Keeper". He is very friendly and warm, and great friends with the bubbly Periwinkle, who is one of the few fairies who actually calls him by his real name instead of "Keeper."
While in his library, Dewey is visited by his friend, Periwinkle, who tells Dewey about a strange event that occurred while she was watching the animals cross the border from the warm seasons to the Winter Woods. While she was doing so, her wings began to sparkle. Dewey was baffled by the story as fairy wings sparkle when another fairy born from the same laugh is near. Just then, a warm fairy named Tinker Bell appears to ask Dewey about the wing phenomenon as well. Dewey then realizes that Peri and Tink were born from the same baby laugh, making them sisters.Dewey was excited about the entire spectacle until Lord Milori arrives. Milori speaks to Dewey about a book that mysteriously appeared in the Winter Woods. Milori fears a warm fairy is in the Winter Woods which is forbidden. Milori then commands Dewey to ask any warm fairy that crosses the border to leave. When Milori exits, Dewey is stuck with the task of telling Tink to return home. Dewey instead allows Tink to stay for the day, before nightfall. Tink and Peri take the time to bond and connect. That night at Peri's house on a mountain cliff, Tink sets a fire to warm herself, but the fire breaks the thin ice she and Periwinkle were sitting on. Because her coat is covering her wings, Tink is unable to fly and begins to plummet to the ground. Dewey rescues the tinker with his pet lynx, Fiona, and agrees that the Winter Woods really is too dangerous for a warm fairy. Dewey and Fiona give Tink a ride to the border that separates Pixie Hollow and the Winter Woods. While Dewey is covering his eyes to prevent himself crying, Tink and Peri think of a way to continue seeing each other. The next morning, Peri visits the warm seasons via a snow making machine created by Tink and her friends. When the machine dies down, Peri is rushes home. Lord Milori notices Peri's wings decaying and declares that she and Tinker Bell may never see each other again. Afterwards, the snow making machine goes on the fritz, endangering the Pixie Dust Tree and all fairy life. Tink tells Peri, Dewey, and the others that if they can preserve the Pixie Dust Tree with their ice abilities, fairy life would be saved. While Peri and her friends Spike and Gliss forge on, Dewey rounds up Lord Milori and an army of frost fairies. Together, the frost talents are able to preserve Pixie Hollow, and when the ice melts, everything is still alive and well. In the end, Lord Milori and Queen Clarion abolish the border law, realizing keeping Peri and Tink separated was a mistake. Dewey is last seen at the big celebration, signing an autograph book for an admiring warm fairy.
- Dewey shares his name with the Dewey Decimal System, a method for arranging books in libraries.
- Dewey is a fairy that has an elderly appearance, but he was born this way, because his status as The Keeper suits someone older and wise.