The DigiDestined continue in their work to clean up the Digital World. As another day comes to an end and the group celebrate a job well done, Ken seems nervous about something. As ever, Davis is quick to notice, and after he attracts the attention of the group, Ken is forced to reveal the festive envelopes in his hand. T.K. quickly works it out and saves Ken the trouble of making a stuttered announcement, that he would like to invite the group to a Christmas party. The reaction is generally positive, and the Digimon quickly make sure that they're not left out of the fun. However, Cody, whose relationship with Ken is still somewhat icy, remains distant from the group, and so Ken approaches Cody himself and hands him his invitation. Cody seems surprised, though he thanks Ken, and the two finally seem to make amends.
Meanwhile, in the real world, the holidays have already begun. Matt rehearses for a Christmas concert with his band, Arukenimon tries to come up with another fiendish plan, and T.K.'s mother meets with Davis' father at the shopping mall. After finishing their meeting, she heads off along the promenade, only to be halted by a shady figure in a purple trenchcoat. She identifies him as "Mr. Oikawa", a man who investigated the mysterious happenings at Highton View Terrace eight years ago. Oikawa warns her that a new monster problem is beginning, and that she should be careful who she lets her children hang around with. T.K.'s mother is clearly taken aback by these words, and inquires as to why he's saying all this. Oikawa leaves her with a hazy response before wandering off and disappearing altogether.
Back in the Digital World, Davis and the others meet up with the rest of the Chosen Digimon as they prepare to give the older DigiDestined a Christmas present they'll never forget. And they certainly aren't disappointed when their Digimon greet them in the real world. As Matt gets back to rehearsing for his concert, Sora makes her way to the practice room with a gift for him, and runs into Tai just outside. Tai asks her if she's going to the concert with anyone, and she nervously tells him that she'd like to be available for Matt. Tai is quick to understand the situation, and reassures Sora that he's okay with it, giving her a gentle shove towards the nearby doorway, where Gabumon is now waiting. Agumon comments afterward on how Tai how has really grown up, before Davis' sister Jun charges past them and into Matt's practice room.
Later on, the younger DigiDestined arrive at Ken's home, and he shows them into his room. Yolei comments on a picture of his brother Sam, making a slight faux pas by mistaking Ken's brother for him. At the same time, Matt's concert is finally getting under way. At least, until a DarkTyrannomon crashes through the stage's backdrop, accompanied by a horde of Bakemon. Agumon and the other Digimon attempt to digivolve, but fail, forcing the group to retreat from the concert tent. Outside, the DigiDestined discover a whole host of other Digimon running amok, and a control spire, explaining why the Digimon are unable to digivolve.
While all this is happening, the other DigiDestined at Ken's home are playing a card game, and Yolei becomes infuriated after losing. This causes everyone to chuckle, and Ken laughs out loud, surprising everyone in the room. Ken becomes sheepish, causing the group to laugh even more. In the kitchen, Ken's mother is over the moon at how well Ken is doing with his new friends, though the phone goes off before she can get any more misty-eyed, and it turns out to be Tai, who's calling Kari and the others for help. They react swiftly, and soon meet with the older DigiDestined. Their first move is to destroy the newly erected control spire, allowing the rest of the Digimon to digivolve and fight. Rather than destroy the rampant Digimon, the DigiDestined decide to go about rounding up the Digimon and sending them back to the Digital World via Izzy's laptop. The last few Digimon turn out to be tougher opponents than the previous, and so the Digimon DNA digivolve, giving them the extra strength they need.
Once the chaos is over, the group come to the conclusion that Arukenimon must be behind this, and prepare themselves for more trouble ahead. Though in the meantime, the kids wish each other a Merry Christmas, and head home to enjoy the festive season, while it lasts.