At the beginning of Winter, everyone prepares for the final season of the year. Tinker Bell wants to go to the Winter Woods due to her curious nature. She sees that the tinker fairies make snowflake baskets which are carried by snowy owls, who then delivers them to the winter fairies, and learns that there will be another shipment tomorrow.
Later that day, Tinker Bell volunteers to help Fawn take the animals to the Winter Woods to hibernate. While Fawn is busy Tinker Bell crosses the border into the Winter Woods, and her wings start to glow. But Fawn warns her that her wings are freezing and rushes her off to the fairy hospital. After being examined, Tinker Bell remains curious about the sparkles and colors her wings made in the Winter Woods.
So Tinker Bell flies off to the Book Nook, where she finds a book titled Wingology, but unfortunately, the page on "Sparkling Wings" has been chewed up by a bookworm. A reading fairy tells Tinker Bell that the author of the book, the Keeper, might be able to help her, but he lives in the Winter Woods.
Preparing herself for the Winter Woods and using the final shipment as her only chance, Tinker Bell sneaks into the workshop and climbs inside one of the baskets and waits for the owls, with help from her friends Clank and Bobble. She gets picked up by an unexperienced owl and makes her way across the border.
Suddenly, the owl accidentally drops the basket, and Tinker Bell crashes into the snow. Realizing her book has been flung from her bag, she tries to get it back before anyone finds it. However, Lord Milori, the Lord of the Winter Woods, finds the book and asks Sled, an animal fairy, to return the book to the Keeper. Using this as an opportunity Tinker Bell follows Sled to the Winter Library.
Upon arriving, she spots the Keeper, Dewey. But before she can talk to him another fairy rushes into the room and proclaims that her wings were sparkling the day before when Tinker Bell's wings begin to glow and sparkle.
Tinker Bell meets the frost fairy, whose name is Periwinkle. The girls ask Dewey to explain what was happening to their wings. Bringing Tinker Bell and Periwinkle to a platform and positioning their wings, the whole chamber becomes filled with images of the mainland. They see a baby's first laugh that splits in half and journeys to the Pixie Dust Tree in the form of two white dandelion seeds. Tinker Bell and Periwinkle realize that they are sisters.
Suddenly, Lord Milori arrives, concerned about the book, warning Dewey to send any warm fairy back to the Warm Side. Dewey tells the two they can spend a day together before Tinker Bell has to return home. Periwinkle shows to Tinker Bell the things she collected and tells them she calls them "found things" to which Tinker Bell calls lost things.
Next, they go to the Frost Forest to meet Periwinkle's best friends Gliss and Spike. They skate on the ice and the bond between the sisters strengthens even more. They joyfully spend the whole day together.
That night at Periwinkle's home, as Tinker Bell builds a fire to stay warm, she realizes that if she can make it warm in the Winter Woods, she can make it cooler at her home. Suddenly, the snow floor melts beneath them, it is weakened by the fire. After the incident, Dewey tells the girls that Tinker Bell has to go home. The girls realize that they might never see each other again, but Tinker Bell comes up with a plan. When the three fairies reach the border, Tinker Bell whispers to Periwinkle to meet her at the border tomorrow.
