In the Yukon Territory of Canada, Nathan gets out of bed. Santa Claus is on the roof. Nathan sees the cookies and milk and only a few presents. Then Santa falls off the roof but magically returns to his sleigh. Nathan returns to where the tree is and sees many more presents, the milk gone, and a bite taken out of a cookie. He puts the cookie in a plastic bag and seals it.Thirty years later in Santa Barbara, California, Nathan finds the cookie still preserved in the freezer and tells his 13-year-old son Tommy it is a cookie Santa took a bite out of. Tommy, who wants to be a detective and only deals in facts, refuses to believe. His younger sister Suzie still believes in Santa. In order to prove Santa took a bite out of the cookie, Nathan realizes DNA testing is now possible, and his wife Janice, a pediatrician, works where that can be done.There will not be a white Christmas. Everyone is dressed like it is still summer.The family goes to an animal shelter and looks at dogs. Nathan doesn't really want to take one home but Suzie can't resist a dog she calls Rusty. The dog has a thyroid problem which requires him to take pills. Still, Nathan agrees they can take Rusty home.But Janice refuses to have a dog. As Nathan drops the children off at her house, he must take Rusty back home and take care of him.As he takes care of Rusty, Nathan designs his latest toy, a stuffed Dodo bird. But the toy is nothing special, according to a toy company representative. Nathan will have to add something to it for it to be accepted.Suzie asks her mother why her parents don't live together. Janice assures her she still loves Nathan, but says Nathan needs to grow up.When the kids come back home, the same question is asked. Nathan says he loves their mother. It is uncertain whether they will get back together, though. Tommy dislikes having to share a room with his sister, but obviously Nathan is not in the best financial situation.It is Christmas Eve and the kids must go to sleep or Santa won't come.When Santa arrives, he takes the presents out of his bag and Rusty gets in the bag without Santa seeing.The next morning, the kids are so happy with their presents until one for Rusty is opened, and they realize Rusty is nowhere to be found.Santa Claus arrives back at the North Pole, which from the air looks like a hurricane with a visible eye. Wife Carol is happy to see him and serves him tea. The elves are still busy. Most of them look like children but talk like they are on helium. One named Elfis looks like Elvis in his later years, with sunglasses.The family searches the neighborhood and puts up flyers.Rusty appears at Santa's workshop and no one knows where he came from. It is obvious some family is missing their favorite pet, but how to find out who? There are billions of possibilities. One of the elves does research and finds out the dog is a Japanese breed, so the search begins in Japan. Ying and Yang search every house.The KBMS newscast has an unusual story: a hot blonde weather girl gives the North Pole forecast and then shows NORAD footage of Rusty in Santa's sleigh. The kids see Rusty and realize that is him. Santa stole their dog! Actually, Tommy doesn't believe it is Rusty but a dog that looks like him, and of course he believes the footage must be fake.Back at the North Pole, the weather girl thanks her cameraman and Santa uses his magic to change her back into the elf Snowflake. It is hoped this news story will help them find who the dog belongs to.Suzie writes a letter to Santa (with her mom's return address) and asks the postman to deliver it. She also appears on a KBMS newscast to announce to the world Santa stole her dog. Santa sees this and is upset that now kids won't trust him any more.The kids' parents are at a martial arts demonstration with both Tommy and Suzie participating. Nathan and Janice discuss the possibility of Nathan taking the kids to see their grandmother, who still lives in the Yukon Territory. Janice doesn't want him taking the kids out of the country, but they've never met their grandmother, who doesn't want to move, and they've never seen where he grew up, or snow. Besides, it's close to the North Pole, and if they go there, they can get Rusty back. Janice finally agrees.The family arrives at an airport that is not busy, and gets on a plane that is not full. Suzie tells the flight attendant they are going to the North Pole to see Santa Claus.In the Yukon Territory, the family arrives at Nathan's childhood home, which is really nice. Nathan's mother is so happy to see them, and even Tommy is happy to see snow.After they spend some time together, the family is ready to take their trip to the North Pole. Nathan's mom has a Honda SUV with the name of the family business still on the side. It will still run after not being used for three years because the battery was disconnected.The family must cross the border into Alaska. This means showing their passports, and of course Suzie tells the guard where they are going. He believes them.The family has quite an adventure, almost hitting a reindeer. The SUV won't start but the situation is not that bad since it was just a loose connection to the battery. But Nathan believes a mechanic should look at the SUV and they will stop in the next town.The sign in the town says Anchor Point, the westernmost point on a highway in Alaska. But the family is told they are in North Pole, Alaska. While they are there, someone dressed as Santa Claus steals their stuff out of the SUV.The family meets Elroy, who wears an apron and a chef's hat and appears to be Tommy's age. He even has braces. However, he says he is 300 years old. Elroy explains that people think they are at the North Pole when they are in the town, but it is actually farther away, as he shows them on a globe. It is actually in the Arctic Ocean so they won't be able to drive there. Elroy also says he can help the family, and he shows Suzie the letter she wrote, because he is in charge of letters to Santa that arrived in North Pole, Alaska. He also says he is having trouble getting back home, because his special magnet which finds the Magnetic North Pole is missing. All of this is too much for Nathan, who just wants to go back home once their passports and other stuff are found.Young Nathan gets a visit from Santa, which adult Nathan is able to see with what he is told are virtual reality glasses. Santa tells young Nathan that his adult self is in trouble.And miraculously, the police are able to find who stole everything, and Elroy's magnet, which causes chaos. They are asked to identify the Santa in a lineup. It turns out to be Kyle, who is a kleptomaniac. But he also saved a family from a fire several years ago, and was so seriously burned that he wears gloves and covers himself up so people won't see his scars. When Kyle stops Suzie from being hit by a car, the family agrees to take him with them to the North Pole, as well as Elroy, who turns himself small and rides in the glove compartment. Kyle rides in the trunk.Back in California, the DNA results are in. Janice is told whoever ate the cookie is 1000 years old and has DNA representing all ethnic groups.At the North Pole, the mystery is solved and Santa takes Rusty back home.The family must make one more border crossing. The Russians control the pole, so the next border guard is Russian. Suzie nearly gets the family in trouble by mentioning Elroy and Kyle, who don't have passports. But it appears Suzie has two imaginary friends, so they get through.The brakes go out on the SUV and it goes off a cliff. But then the SUV is floating above what looks like the eye of a hurricane. The family has arrived at their destination. But Santa is not there.While they are waiting, Suzie asks Kyle to tell her the story of how he saved the family. She tells him he is a hero, and he takes off his gloves. His hands don't look so bad. Suzie also learns that due to global warming, if nothing is done, Santa's workshop will end up in the ocean.Janice wakes up to find Santa in her house with Rusty. Left with the dog, she must now take care of him.Elroy turns Dodo into a digital assistant which knows everything like Siri or Alexa, and many of the new and improved Dodo are produced to deliver in the future. He also turns the SUV into a toy so it can be taken home.Santa returns home and gives medallions to everyone. Most of them say "Good Boy" or in Suzie's case "Good Girl". Kyle also gets one that says "Bad Boy" but he is put in charge of the naughty list. He will be given not a sleigh and reindeer, but a toboggan and donkeys, with which he will deliver coal.Santa returns the family to Janice's house. They stay there for the night and Janice seems to have adjusted to having a dog. She also seems open to reconciling with Nathan.The next morning, the toy SUV has mysteriously returned to normal size. They were supposed to park it outside but forgot.A cat watches a KBMS newscast as Santa delivers toys.