Franklin the Turtle, [Noah Reid], his little sister Harriet, [Bryn McAuley], and their parents, Mr. Turtle, [Richard Newman], and Mrs. Turtle, [Elizabeth Saunders], plan to spend Christmas with their maternal grandparents at Faraway Farm, a cozy place far from Woodland where Mrs. Turtle grew up. As they prepare to leave, they sing the first and third verses of Deck the Halls.
Franklin immediately becomes annoyed with Harriet when she throws a snowball at him, causing him to drop a large pile of presents. Franklin's best friend Bear, [Luca Perlman], and his little sister Beatrice, [Kristen Bone], come to collect Franklin's pet goldfish, Goldie, and Franklin accidentally leaves his favorite stuffed toy dog Sam behind. Franklin thinks Harriet dumped Sam in the snow on purpose, but in reality Beatrice had found Sam and Bear had failed to give it back before they left.
Franklin remains irritated as they arrive at Faraway Farm, and he learns that he and Harriet will be sharing a room. Later that evening, his grandmother Jenny, Grandmother Turtle, [Joyce Gordon], tells a strange story from her childhood about a reindeer. The tale includes a flashback showing young Jenny and her father, Mrs. Turtle's grandfather and Franklin and Harriet's great-grandfather. Jenny admits she might have imagined things, just as Mr. Turtle quietly poses for a family portrait, leaving Franklin looking sadly after Sam. Jenny then shows Franklin Sirius outside and softly sings Twinkle Twinkle Little Star before sending him to bed.
The next day, as Franklin feeds the chickens, Jenny reveals a little surprise: she’s fixing up an old sleigh for Grandfather Turtle. Franklin decides to help, and Jenny introduces him to her neighbors, the Collies, who collect the polish for the sleigh. Mr. Collie, [Chris Wiggins], and Mrs. Collie, [Araby Lockhart], offer their help and friendship. That night, an ice storm strikes, causing a blackout, and while Franklin searches the attic closet for candles, he finds the bell from Jenny's story, proving that she was not imagining the tale after all.
The following morning (Christmas Eve), Franklin shows the bell to Jenny and suggests using it for his grandfather's sleigh. Jenny has Harriet help with the sleigh, but Harriet spills the beans at lunch, much to Franklin's frustration, though fortunately Grandfather Turtle does not overhear. Later, Mr. and Mrs. Turtle go to check on the Collies while Franklin and Harriet continue to work on the sleigh. Despite Franklin telling her not to, Harriet rings the bell, and just like in Jenny's story, a reindeer appears. Franklin runs to the house to tell Jenny. In the process, Franklin distracts Grandfather Turtle, who slips on a puddle of ice and breaks his leg.
Back in the house, Jenny cares for Grandfather Turtle and tells him to rest. Grandfather Turtle comforts Harriet when she cries, and when Franklin admits his guilt, Grandfather Turtle explains that it was an accident. Jenny sends Franklin and Harriet to their room while she tends to Grandfather Turtle.
Determined to make things right, Franklin decides to use the sleigh to go back to Woodland and find Dr. Bear. He soon discovers Harriet has come along, hidden in the back. Rosie the horse pulling the sleigh is just as surprised as Franklin and bolts, leaving the two young turtles lost in the woods. Back at the farm, Jenny finds a note Franklin wrote saying he’s returning to Woodland to find Dr. Bear, and Mr. and Mrs. Turtle hurry back from the Collies’ to search for them along with the grandparents.
Meanwhile, Franklin bluntly scolds Harriet for disobedience, causing her to cry. He apologizes for his harshness, and Harriet reveals that she has the bell. With Franklin’s blessing, she rings it again, and two reindeer arrive. One of them bears the same bell, revealing that the bell belongs to the other reindeer and that its magic calls the first bell. The two reindeer help Franklin and Harriet reach the Bears’ house and fetch Dr. Bear, [Mari Trainor], who provides a cast for Grandfather Turtle and returns Sam to Franklin, much to his delight.
Back at the farm, Jenny and Mr. and Mrs. Turtle split up to search for the children, while Rosie the horse eventually returns. Together, they all witness Franklin, Harriet, and Dr. Bear arriving by sleigh. Dr. Bear treats Grandfather Turtle's leg and, with a happy reunion, returns Sam to Franklin. That night, Franklin and Harriet look out the window and glimpse Santa Claus and the reindeer in the sky. The film ends on a warm note as Franklin and Harriet wish each other a Merry Christmas.
