In Ft. Lauderdale, Florida, Pete and Myka pose as power workers to get to a home where Rudolph’s Nose, a powerful artifact, has brought the Christmas spirit to light. A reindeer slams through the door while animated Christmas lights drags Pete away, while Myka tries to get to the roof but a Santa statue whips her. As Pete is pulled away, he grabs a statue of a choir boy who comes to life and starts beating the agent over the head with his song book. Myka finally manages to recover Rudolph’s Nose and neutralize it. The statues become statues again and the “reindeer” reverts to a dog with antlers, just like it was originally. The young girl who lives at the house, Carie, runs out to get her dog and thanks Pete with a candy cane. Her parents come out and the agents hastily try to explain what was going on.
At the warehouse, Artie is going on a trip to Las Vegas with Vanessa and Claudia tries to give him a new jacket as a gift. He isn’t interested in the jacket and complains that his father has guilted him into taking him along on the trip. Worse, Hugo has found out about the trip and invited himself. Artie tries to back out of the trip by going with Claudia to visit her brother in Switzerland, but she doesn’t want her brother spending his holiday talking shop. Myka and Pete return and Artie tries to convince Pete to give up his warehouse duty so he has an excuse to stay. Pete refuses and Myka offers to take Artie along. However, she points out that Hugo could still be interested in Vanessa and Artie reluctantly agrees to go on the trip.
Pete takes Rudolph’s Nose to the Aisle of Noel to put the artifact back. The area is covered in snow and Pete trips, bumping into a shelf. Several items fall on him, including an upholstery brush, but nothing happens. Pete goes back to Artie’s office only two discover two new warehouse agents, Sandra and Raymond, that he’s never seen before. They draw Teslas and demand to know how he got in. When Pete asks what happened to Artie, James MacPherson comes in and informs him that Artie hasn’t been in charge of Warehouse 13 in a long time.
Pete heads to the Christmas aisle of the warehouse and puts away the reindeer nose. He slips on the snow and several artifacts land on him. Pete puts them on the shelves and goes back to the office, and finds two strangers there, a man and a woman. They draw Teslas on him and demand to know who he is and where Artie is, and MacPherson comes in and says that Artie hasn’t worked there in a long time.
As the agents handcuff Pete, he explains that the last time he saw MacPherson, he had been reduced to ash at the Escher Vault, and that he turned evil before he died. MacPherson, in charge of Warehouse 13, seems impressed that Pete knows Artie. When Raymond takes Pete to the B&B, Leena greets them and Pete tries to convince her that she knows her. She doesn’t, and is surprised to discover that Pete doesn’t have an aura. Sandra calls to inform Raymond that Pete Lattimer isn’t on any of their databases, and Pete grabs Raymond, knocks him out, and takes his Tesla. He tries one more time to get through to Leena, warning her that MacPherson is up to something and using artifacts to whammy everyone. Leena still doesn’t believe him and Pete says that he has to go and find someone to help him. He tosses Leena the Tesla and runs off... unaware that Mrs. Frederic is in the next room, listening to everything he’s said.
Once he escapes, Pete calls Myka’s mother Jean at her bookstore. She’s surprised to learn that Myka has a partner and has no memory of Pete or Edgar Allen Poe’s pen. When he asks for Myka, Jean tells him that Myka hasn’t visited in two years... ever since her father Warren died. Pete insists that the Warren he knows is alive, and Jean hangs up.
In the Secret Service Building in Washington, Myka is working at her desk when Pete gets in using a stolen ID badge. She has never heard of Pete and doesn’t know what Warehouse 13. Even when he tells her intimidate details of her personal life, Myka assumes that he’s read about her on Facebook and is stalking her. When Pete tries to explain that she lives in a warehouse in South Dakota, Myka insists she would never do that and calls in the security guards to take him away.
At the warehouse, Raymond informs MacPherson that he failed to hold Pete, and that the intruder has military training. MacPherson tells Sandra to find Pete.
Pete follows Myka to a bar where she’s working alone. She grabs him and threatens to shoot him, and Pete offers to leave her alone if she answers one question. Myka agrees and Pete asks why she’s spending Christmas Eve alone rather than with the people she loves. Myka awkwardly insists that people love her but can’t name anyone, and Pete tells her that she works in South Dakota in a warehouse because it’s filled with endless wonder. As Myka starts to leave, Pete tells her that in his reality, her father Warren is alive and spending time on Christmas Eve with his daughter. When Pete describes the book that Warren secretly wrote, Myka realizes that Pete knows something and agrees to help him. Pete says that they have to find Artie Nielsen next, and Myka recognizes the name.
Myka takes Pete to the correctional facility where Artie being held after he supposedly tried to assassinate the President of the U.S. three years ago while trying to recover the Bloodstone. Pete realizes that was the mission where he met Artie for the first time, but in this reality Pete wasn’t there. When Pete tells his story, Artie figures that he was affected by an artifact and has Pete identify the artifacts that fell on him. Artie confirms that one of them was an upholstery brush belonging to Philip Van Doren Stern, who wrote the story The Greatest Gift
. The artifact literally swept Pete out of existence, meaning he was never born. Even the candy cane that Pete got from Catie has disappeared because he never went on that mission. Because Pete never existed, Artie ended up going to jail while MacPherson convinced the Regents that he had turned over a new leaf. Further, because Pete helped Myka and her father reconcile, he didn’t suffer from a fatal heart attack brought on by stress. Myka still isn’t convinced but both Pete and Artie insists that she has to free Artie.
Myka tries to convince the prison official to release Artie but he refuses. However, he soon gets a message from Mrs. Frederic authorizing Artie’s release. As they go, Artie warns them that MacPherson injected him with a chemical that reacts to the painite in the warehouse’s paint. Pete knows all too well about it since that’s how MacPherson died in his reality. When Artie wonders how they’re going to break into the impenetrable Warehouse 13, Pete asks if he knows Claudia Donovan.
At the warehouse, MacPherson is going through a list of all the Christmas artifacts. Raymond reports that Artie has been freed thanks to Mrs. Frederic, and MacPherson tells the agent to bring back Artie, dead or alive.
Artie takes Myka and Pete to the Midwest Psychiatric Clinic to see Claudia, who is locked up. Artie goes in first and Claudia locks the door behind him. She has papered the wall with notes on Artie and her missing brother Joshua, Artie’s student. Claudia shocks Artie with a crude cattle prod made from a lamp and demands that he help her bring back Joshua. Pete calls through the door that he knows how to get Joshua back from the interdimensional void, but she has to help them in return. Convinced, Claudia agrees to help them break into the warehouse.
Sandra and Raymond arrive as the quartet leave the clinic. The team splits up and manages to get back together to use Artie as bait to lure the warehouse agents into an ambush.
Mrs. Frederic comes to see MacPherson in his office and wonders why he’s sent agents to hunt down Pete instead of recover Shakespeare’s Lost Folio. When she points out that he didn’t tell the Regents about Pete, MacPherson paralyzes her using DeMille’s Riding Crop, then forces her into the bronzer. As he prepares to encase her in bronze, MacPherson says that he had no choice because she wouldn’t trust him. Once he finishes with her, Sandra and Raymond call to tell him that Pete has escaped with Artie and the others. MacPherson orders them back to the warehouse in anticipation of an attack.
Pete takes the others to the B&B to search for the quartz necklace that will let Artie safely enter the warehouse. Leena, armed with a Tesla, confronts them, and Artie reminds her that she knows him. He asks Leena to trust him and she finally admits that she could sense that something wasn’t right. She welcomes Artie back and gives him the quartz necklace. The team then heads for the warehouse while Pete explains that his Myka smuggled H.G. Wells out through a secret entrance he knows about. She wonders why he keeps talking about the male British author, and Pete starts to explain that H.G. is a woman. They find the hidden entrance, concealed by the doorway to Aladdin’s cage, and Myka is able to speak the proper opening incantation in Arabic. Claudia hacks the electronic lock within and they continue to a room with three doors. Artie warns that two of them lead to fatal traps, but Pete is able to get a good vibe from the right door and they go through safely.
Once in the warehouse, Myka and Claudia stare in wonder at the warehouse. Claudia wants to find the compass so she can bring Joshua back, but Pete stops to remind her that the versions of them that he knows are family, and that they spend every day in a place of endless wonder. Pete and Myka head for the Aisle of Noel to get the brush while Artie and Claudia head for the office to access the computers and figure out how to reverse the artifact’s effects. However, Myka and Pete discover that they’re caught in a trap set by MacPherson, who has used an artifact to trap them in an infinite corridor.
When they get to the office, Claudia hacks the computers, easily bypassing the firewalls. When they access the artifact files, they discover that the upholstery brush isn’t on the shelves. Artie spots a barely-visible MacPherson and pulls Claudia out of the way as MacPherson attacks her with the samurai sword artifact. Sandra and Raymond arrive to capture Claudia and Artie as they try to escape.
Myka figures out that they’re trapped in a Moebius strip and that the only way they can escape is to run in opposite directions. When they do so, they break out of the loop and go to the Aisle of Noel, only to discover that MacPherson has cleaned out the entire section. They go to the office and realize that MacPherson has captured their friends and spot Raymond and Sandra taking them to the bronze section. Using the travel line, Pete and Myka head across the warehouse.
Artie tries to convince Sandra not to bronze them, but she insists that she’s following orders. As the agents lock Artie and Claudia in the bronzing chamber, Artie apologizes to her and Claudia thanks him for saving her from MacPherson. Pete arrives with the elephant cane and uses it to shake the room, giving Myka the chance to take out Sandra and Raymond. After they free Artie and Claudia, they head for the office and Artie explains that to reverse the brush’s effects, Pete has to touch it again. However, Artie figures that MacPherson wants a reality where he’s alive and in charge. Since he doesn’t know which artifact is responsible, he’s taking all the items to the Lehmann Fornax, the warehouse’s furnace.
At the Fornax, MacPherson is on a catwalk preparing to throw the artifacts in. Pete arrives with the others and Artie goes around while Pete distracts MacPherson. Pete tries to warn MacPherson that if he destroys the wrong warehouse, it could blow up the warehouse. MacPherson ignores him and opens the floor panel, revealing the white-hot Fornax beneath. When Pete refuses to identify the brush as the artifact responsible, MacPherson throws them in one at a time. However, Artie sneaks up invisibly using the Lenape Cloak and struggles with his former partner. Artie manages to grab the brush before it falls off the catwalk, but MacPherson grabs the quartz necklace. Realizing he has only one chance to put everything back to normal, Pete tells Artie to throw the brush to him. Artie, trusting him, throws it into the air and then disintegrates as MacPherson pulls the necklace off of him. Pete leaps into the furnace and grabs the brush, plummets into the furnace...
... and finds himself back in the Aisle of Noel as his reality is restored. Pete confirms that Catie’s candy cane is back in his pocket. As he lies in the snow, making angels, Trailer runs up and licks Pete’s face.
Pete then runs to the B&B, where everyone has gathered for Christmas Eve. Even Mrs. Frederic is there, making sure Claudia doesn’t drink any alcohol. They’re all surprised when Pete is overly enthusiastic about greeting them, especially when he hugs Mrs. Frederic. She tells him never to do it again. Myka asks if Pete is okay, and he says that he’s glad to be alive and that he really loves them. They figure that he’s needy and desperate and tell him to sit down and watch the big boxing match at the MGM Hotel in Las Vegas. However, as they tune in the fight, they discover that it’s been preempted by It’s a Wonderful Life