It is Christmas time at Mutt & Stuff, and Calvin and Zippy are busy finishing the decorations as Zippy puts a star on top of the Christmas tree and then hands Calvin the remote to turn on the Christmas lights as a gift when he arrives.
Soon after, they ring the school bell to summon the dogs, and as the kids bring their dogs to drop off at Mutt & Stuff, Stuff joins them this time in one of his rare instances of arriving with the other dogs instead of waiting until after all the dogs have been dropped off first to make his arrival to the school. Stuff is very excited for Christmas, and once inside, Calvin sees which of the dogs have been naughty or nice. They have all been nice, and as Calvin reads off what gift each dog wants for Christmas, he notices that Stuff has not wished for anything. Stuff explains that he is unsure what to pick.
While Stuff decides on his Christmas wish, it is revealed that Cricket wishes to see snow, but since the doggy weather forecast calls for sunshine all week, Cricket may not get her wish, until Stuff brings up Phil the Snow Dog. Calvin then reads a story about how Phil travels the world, and if he finds dogs who show the Christmas spirit very much, he makes it snow as a reward. This inspires Stuff into thinking that if they show a lot of Christmas spirit, maybe Phil will come and grant Cricket's wish. To that end, Calvin and Stuff do their best to show the Christmas spirit with the help of the other dogs.
First off, they have Music Class, where Stuff sings a doggy version of "Jingle Bells" while aided by the other dogs. Afterwards, he then tries an encouraging cheer for Phil, while Calvin checks out the puppies to see how they are getting into the Christmas spirit, complete with Grandma dressing up as Santa for the puppies. Melvin the Fire Hydrant even tries to help out Cricket with a Christmas joke to boost her spirits. Despite all that, there is still no sign of Phil, or snow, and Stuff is growing disheartened by how Cricket may not get her wish, though he has made up his mind on his Christmas wish: Stuff's wish is for Cricket to see snow. Calvin suggests making it snow inside with a little Arts & Crafts Class. After the dogs are able to grant Cricket's wish in their own way, Calvin's father, Cesar, arrives to deliver the gifts to the dogs, but Calvin first has to figure out how to get them inside without the dogs noticing, and decides to have them go to sleep for nap time.
With the dogs all asleep, Calvin and Cesar are able to bring in the gifts and put them under the tree. With everything set, they wake the dogs with a cry of "Merry Christmas!" and pass out the gifts to the dogs. Many of the dogs get what they wished for, and even Cesar and Calvin have gifts for each other: Matching sweaters. Afterwards, Cesar realizes they never got Stuff anything, but when talking to him, Cesar had learned of Stuff's wish, and is proud of him. Stuff is proud of himself as well, but is disappointed that it might not snow until next year. However, Cesar notices that it has started snowing outside, and when pointing it out to Stuff, Stuff cannot believe his eyes and calls Cricket over to show her that her wish came true. Calvin immediately tells the dogs to bundle up as they are heading outside to play in the snow.
Outside, the dogs, Calvin, Cesar, and Stuff, enjoy playing in the snow, and soon after, Stuff wonders if Phil saw that he had really shown the Christmas spirit with helping out Cricket. He is soon shown that Phil did see what had happened at Mutt & Stuff, and had shown up in person to reward Stuff with the snowfall.
Stuff declares it a Christmas miracle, and is allowed to lead everyone in a doggy version of "Joy to the World" to celebrate before Calvin has everyone join in the trademark doggy dance party at the end of every episode of Mutt & Stuff. The kids who the dogs belong to join in with Cesar, Calvin, Zippy, and Stuff to dance and celebrate as Calvin wishes the audience a Merry Christmas from all of them at Mutt & Stuff.
During the special, the cats Davenport and Zoey have a couple of laughs with Christmas jokes they make, but at the end, they decide to enjoy the snow in a quiet moment together...Before Davenport ruins it and causes them to fall out of the tree as a result. Despite that, they offer one last Christmas farewell to the audience to show they are alright and will see them next time on Mutt & Stuff.