The episode starts at South Park Elementary. Kids are running about the place, destroying file cabinets and papers. Clyde runs in with a burning torch, setting the papers on fire. Cartman says the school canceled Colombus Day, which means that they have to come to school on Monday.
At the South Park Elementary Gym, a man named Peter Galtman says that the school won't celebrate Colombus day. The parents are shown as he addresses them.
A statue of Colombus is shown, Randy comes in out of nowhere and encourages everybody to take it down. Randy climbs on top of it and tries to remove it, people watch him confused. A rope gets wrapped around the statue and Nelson uses a car to pull it down. The statue falls down as people look on.
At the Marsh residence, Kyle calls Stan about his dad wanting to cancel the holiday. Stan quickly ends the call as Randy comes in with his laptop. Randy tells Stan to call various people and harass them, particularly people living in Colombus, Ohio.
A reporter talks on the issue as a statue is shown. It is revealed Randy crapped on it and he is interviewed. Randy says he has an issue with the indigenous people of New York City. The reporter, who is confused ends the report.
Back at South Park Elementary, students are crying in the cafeteria. Stan sits down and Cartman makes fun of him. Kyle says finding out what makes Colombus so offensive may help. Kyle gets on his iPhone and starts searching. He tells Stan he needs to talk to him.
At the Marsh residence, Randy is on the computer as Stan and Kyle come in. Stan holds up a photo of Randy dressed up as Colombus. Stan keeps holding up various photos as Randy tries to explain himself. He says it's only a matter of time before other people find out.
Randy is on the couch watching TV when an advertisement comes on for DNAandMe. The service claims to help people discover their ethnic backgrounds by doing a mouth swab. Various people are shown praising the service.
At the Marsh residence, Randy is having a group of people over. He goes into his office and gives a Native American money and they start to make out. Randy walks downstairs and says he is ready for his test. A man pulls out the DNAandMe kit and swabs Randy's mouth.
At the Galtman residence, the phone rings and Peter picks it up. A distorded threatening voice is heard telling him to go on Instagram for images of Randy. Kenny, Stan, Kyle, and Cartman are shown in the school bathroom. Kenny is holding a napkin up to his phone to disguise his voice. Kenny threatens to make Peter suffer if he doesn't do what they demanded.
At the Marsh residence, Shelly is in her room drawing when Randy bursts in. He says everything Colombus has to be thrown out. He goes to Sharon as he frantically searches for Colombus kitchen items. He holds their wedding picture where he is dressed up as Colombus in the picture. The doorbell rings and he goes out to investigate, assuming it is his DNA results. He finds the Native American from earlier at the door, with flowers. Randy accepts them and shuts the door.
Back at the Galtman residence, Peter answers the phone once again as Kenny again threatens him to make Colombus day a holiday. Stan and Cartman tell Kenny to speak in a more meaner voice and they are heard talking to each other on the phone in the discorded voice. They argue about cutting his dick off when Stan grabs the phone and says Randy and Peter will pay.
Sharon is sitting in bed reading when Randy comes in, trying to find his other Columbus things. He grabs an orb and staff from the closet and runs outside to bury it. The Native American is at the door once again, singing a song to Randy. Randy pushes him away and kicks him down. A man across the street is seen, videoing this. Randy warns him not to post it online, but he runs away. Randy follows in pursuit.
At the South Park Elementary playground, the boys sit depressed. Cartman comes over and gives a pep talk, saying that Colombus believed every kid deserved a day off school. Kyle looks over at him, as do the other boys, energized by Cartman's speech.
Sharon is on the toilet looking at her phone when Randy says the DNA test people are on the way. He goes downstairs to find the Native American in the living room. The doorbell rings and Randy push him out the back door. He opens the front door and the DNAandMe people tell him the test has to be done again. Randy runs back out to find the Native American and kisses him yet again. He goes back and is told the test includes an anal swab. Randy yet again runs out looking for the Native American but he is stopped by the DNAandMe people who pull him back inside.
At the Marsh residence, the boys are dressed up. Cartman has a horse head on, Stan a pig head, Kyle a rabbit head and Kenny a bird head. They bring in Peter Galtman, who is tied up and blindfolded. He says he refuses to look at Instagram because everything online is fake news. Stan pulls out a VHS tape and puts it into the player. They unblindfold him and Randy is shown kicking the Native American.
At the DNAandMe headquarters, a DNA specimens room is shown with a "Do Not Contaminate" sign. Randy is dressed in black and he sneaks over to the room. He starts to pick the lock when the DNAandMe employee discovers him and asks him what's going on. They tell Randy they have his DNA results. Randy is sitting in a chair, as the employee starts to go over the results with him. Randy is upset to see that he has no Native American in his test results. But he is 43% Northern European, 37% Mediterranean and 18% Southwest Asian. His profile closely matches a standard Caucasian British person. Randy sighs but the employee surprise him, saying he is 2.8% Neanderthal. The employee tells Randy that the species was wiped out, but that some people still possess the DNA because of cross-breeding. Randy says his species was wiped out from the DNA testing, and he goes into a rage. He is shown kicking some file cabinets in the office.
Randy arrives home, depressed. He is surprised to see Peter and the boys there. He asks to speak to Randy, but Randy punches him in the face. He opens the door to find the Native American, who brought his parents with him. He tells Randy to stop pretending with himself. Randy reflects on this, saying that being a victim has downsides.
Outside of South Park Elementary, Randy is speaking to the town. He announces Colombus day has been reinstated. He encourages people to take a day to rip on each other, and with that, they rename the day to "Indigenous Peoples Day". Dave calls Randy an idiot as they start insulting each other, some people walk off as the episode ends.
AV Club gave "Holiday Special" a "B" rating saying: "So maybe that’s the more entertaining takeaway from “Holiday Special”: Randy’s an idiot. It’s a thesis we’ve heard many times before and will probably hear many times again. And unlike the episode’s more substantial message, I’ll likely never get tired of hearing it. As long as I don’t think about it too much."
IGN gave "Holiday Special" a "8.5" rating saying: "While not quite as strong overall as last week's installment, "Holiday Special" is the episode that best lives up to the promise of what South Park is supposed to be this year. This episode focused a bit less on topical humor and headlines, opting instead for a hilarious, Randy-driven storyline that hearkened back to the show's golden era. If this is a sign of what to expect from the remainder of Season 21, then things are looking pretty rosy for this series."