As Christmas approaches, Walter, Jonathan Goldstein and Audrey, Nancy Sullivan, head off for a tropical vacation, leaving Drake, Josh, and Megan at home to hold down the fort. Drake, eager to throw a big rooftop party, plans to host it above Josh’s workplace, the Premiere Theater. Josh’s boss, Yvette Nicole Brown, gives the green light on one condition: Drake must dress as Santa at the mall to supervise the event.
While trying to dodge a kiss, Drake inadvertently makes an unbreakable promise to a little girl named Mary Alice, Bailee Madison, to deliver the best Christmas ever for her family. The plan kicks off with excitement, but it quickly runs into trouble when uninvited guests crash the house party. Josh calls the cops, and a mix-up lands him in custody. In the cell, he bonds with his tough-guy cellmate Bludge, Kimbo Slice, who pretends to beat him up to keep up appearances with the other inmates.
Determined to honor his promise to Mary Alice, Drake tries to orchestrate a breakout to help Josh, but both brothers are caught and arrested. Helen, their determined lawyer and Josh’s boss, Yvette Nicole Brown, appeals to the judge. The judge, Henry Winkler who presides as Judge Newman, decides that Drake and Josh won’t face jail as long as they can fulfill the Christmas wish. A stern parole officer named Perry Gilbert, David Pressman, makes their life difficult, threatening to mobilize the foster family vote against them if the “best Christmas ever” isn’t delivered.
The brothers eventually meet Mary Alice’s foster family: the feuding twins Lilly and Violet, Cosette Goldstein and Camille Goldstein; Zigfee, a boy who speaks an unfamiliar language, David Gore; Trey, the know-it-all kid, Daven Wilson; and Mary Alice’s older, rebellious brother Luke. Gilbert sabotages their efforts at every turn, forcing Drake to try creative fixes to salvage the season. To raise the stakes, Drake bribes Megan with a rare Royal Smith oboe, a family heirloom, but the gesture backfires when Megan discovers the item is a fake.
As the situation intensifies, Gilbert reveals a personal Christmas heartbreak: as a child he longed for a live chimpanzee, but the animal attacked him and urinated on him when he finally got one, turning Christmas into a painful memory. This revelation fuels the brothers’ resolve to bring joy to Mary Alice’s family. They attempt caroling, hoping music will soften hearts, and even enter a Christmas parade that Drake had previously avoided.
In a misunderstanding during the parade, Crazy Steve, Jerry Trainor, is tricked by Gilbert into calling out the truth about the promise, which nearly costs them the chance to make things right. Mary Alice and her family, feeling betrayed, leave—heartbroken—believing the promise won’t be kept. Undeterred, Drake and Josh pull out all the stops, even borrowing Crazy Steve’s woodchipper named “Sally” to create a snowy effect by blasting ice across the neighborhood. The plan backfires in spectacular fashion, causing property damage and sending the brothers sprawling.
Gilbert, who had secretly been gifted a chimpanzee by Josh, returns home and begins to rediscover the holiday spirit. The misadventure earns him a second chance, and with Gilbert’s new empathy, the kids return to the living room with fresh hope. The next morning, Mary Alice’s family learns the truth: Drake and Josh truly did want to help, and their good intentions win the day. They vote “yes,” the charges are dropped, and a belated Christmas miracle unfolds.
Bludge, dressed as Santa, slides down the chimney to deliver gifts to everyone, including the real Royal Smith oboe for Megan. Walter and Audrey return from their vacation aboard a dilapidated hut that blows away in a tropical storm, bringing an ironic end to their getaway. Steve’s improvised “Sally” snow machine finally produces a whimsical, cheesy snowfall, and the house—alongside the neighborhood—enjoys a memorable, if unconventional, Christmas together. The story closes with a sense of shared warmth and outlandish cheer, a reminder that even mischief can lead to genuine holiday joy when families come together.
