Plot

Santa or at least the Spirit of Santa is kidnapped by the Serpent Brotherhood. The Librarians are tasked by Mrs. Claus to rescue Santa in London.

Christmas and the future of the world is threatened when the Serpent Brotherhood kidnaps Santa Claus. The Librarians and Colonel Baird travel to London to rescue Santa, and then must get him to Alaska and the Aurora Borealis. In Alaska, Colonel Baird spreads hope throughout the world with the help of Santa.—John Heckenlively

Santa is volunteering at a soup kitchen in London. Rather than the traditional fat, bearded Christmas icon, he's a middle-aged man wearing a fancy suit and a nice hat. A man comes with a shotgun, trying to steal donations from a volunteer Santa who's dropped into the kitchen, but the real Santa talks him down, looking into his heart to find the good in him. However, Santa is then shot with a mistletoe tranquilizer and realises the robbery was a trick to make him reveal himself.

At the Annex, the team prepares for Christmas, with varying levels of excitement. Cassandra loves Christmas and is enthusiastically decorating, while Jacob wraps presents for his family members. Eve is in a bad mood, as Flynn's desk keeps resetting itself, and she's not into Christmas cheer. The others defend Christmas: Cassandra adores it, even though her parents revealed that Santa wasn't real to her at the age of three and she wishes she could have believed a little longer. Jacob likes seeing his nieces and nephews and misses spending Christmas Eve with his cousins, which often involved a bar brawl. Ezekiel loves Christmas and how clearly marked expensive goods are at that time of year, although when pushed, he admits that he sometimes wonders what it would be like to be a good guy.

Suddenly, Jenkins interrupts the annex-decorating festivities to say that Christmas is cancelled: Santa has been kidnapped. As the team reacts to the news that Santa is real, Jenkins explains that Santa isn't actually the figure they've been led to believe, but an immortal avatar of good cheer. Santa collects good will throughout the year and returns it on Christmas. But if he fails to do so, there will be worldwide chaos. That's why folks are cranky during the holidays: they're running low on good will.

Jacob and Cassandra go to the soup kitchen and learn that the kidnappers had snake tattoos, and realize that Santa has been kidnapped by the Serpent Brotherhood. As they try to track down the kidnappers, Cassandra recognizes Dulaque in surveillance footage and points him out to the others, who had only met Lamia when the Brotherhood had made their attempt to bring magic back into the world. Jenkins seems intensely shocked to hear that name, and obviously recognizes Dulaque. Jenkins determines that they are planning to kill Santa on Christmas Eve at midnight in order to absorb his stored magical power.

At the Serpent Brotherhood's base in London, Santa is being held hostage, but doesn't seem overly concerned about it. He speaks to Lamia, telling her that he's disappointed in her, as he knows she wants to help people, but she's going about it the wrong way. However, he's once again tranquilized by Dulaque before he can finish the conversation.

As Cassandra was taken to the Brotherhood's base while she was working with them, they realize that they can use her memory to help them figure out its location, even though she was blindfolded at the time. While Ezekiel hacks into London's many surveillance cameras, Eve walks Cassandra through using her other senses to recall what else she experienced when she was taken by the Brotherhood. The clues she offers up help Ezekiel determine the right street, while Jacob uses his architectural knowledge to find the exact house.

Jacob and Eve make their way inside the Serpent Brotherhood's lair, where Jacob is distracted first by the amazing art collection, then by Lamia flirting with him. Dulaque orders his underlings to kill them, but Jacob and Eve interrupt them by throwing the many rare and expensive items on display in the room towards the members of the Brotherhood, forcing them to focus on catching the art.

Meanwhile, Ezekiel and Cassandra slide down a chimney into the room where Santa's being held. Cassandra is elated to learn that Santa knows her name, while Ezekiel seems concerned when Santa informs him that he's been a bit naughty.

Dulaque and Lamia realise that Jake and Eve are stalling, so they run off to get to Santa, leaving Jacob to catch the last falling statue himself. When they get to the room, they find that Santa's gone. Dulaque says they won't get far, as Santa "won't be feeling quite himself".

Cassandra and Ezekiel get Santa to Eve and Jake. When Jacob introduces himself, Santa says that he knows him, "both incarnations" of him, which causes Jacob to look unsettled. He says he needs to get to his sleigh to get to the North Pole. Eve reluctantly agrees to help him find his sleigh, even though she's already annoyed by the fact that Santa speaks in the third person. She puts Santa's hat on Ezekiel so he can serve as a distraction, along with Cassandra and Jacob, while she takes Santa to the rail yard where he left his sleigh. Unfortunately, when they get there, they find out that Santa's sleigh has been stolen.

Ezekiel seems thrilled to spread good will while wearing the hat, and even showers a homeless man with money.

As Eve tries to find the sleigh, Santa shifts and goes invisible, reappearing as a Serpent Brotherhood thug attempts to attack Eve. He uses a staff that he's suddenly holding to take down the attacker, and also magically puts a small toy into Eve's shoe.

Eve finds and old, red truck, and starts driving them away from the rail yard. She calls Jenkins, who realizes that Santa has changed incarnations and is now Nikolas the Wondermaker, a much more trickster-like character who left gifts in children's shoes. Something's off about Santa, and he can't seem to keep his incarnations straight. As it turns out, his hat is a talisman: an anchor that helps him maintain his current incarnation, which would explain why Ezekiel's so set on spreading Christmas cheer. Without it, he's more susceptible to the poison administered by Dulaque through the darts. Jenkins advises Eve that they need to keep moving, otherwise Santa can be tracked because of all his magic.

Eve isn't happy about being stuck on a road trip with Santa, and decides that she'll call him "Nick", as she can't bring herself to call him Santa. He tries to talk to her about her dislike of Christmas, but she cuts him off, saying that the real Santa would understand why she doesn't like it. Jenkins asks if they've made any progress in getting to the North Pole, and Eve points out that there's no way she can drive them there. Santa uses his magic to super-speed the truck, but it runs out of gas in Canada, stranding them.

The other three return to the Annex, where Ezekiel continues to spread Christmas cheer, donning a festive apron to make hot chocolate and cookies, and stuffing stockings. Cassandra determines that the North Pole is special because of the ley lines, and calculates a place where Santa can spread Christmas cheer using the northern lights.

They tell this news to Eve, and send Cassandra and Ezekiel to get a plane ready at an airport in the area, while Stone heads into a small town nearby to meet up with Eve and Santa and find them a car. Eve and Santa start walking, and Santa offers up some insight on how Eve never felt like she belonged on Christmas because she's always been moving, spending her Christmases on different army bases as a child and in different war zones as an adult. When he tries to tell her that being with other people means she belongs, that the entire human race belongs together, she points out that she was in most of those places on Christmas because the people there were fighting each other, even on Christmas. Santa says that while people's actions can't be undone, their hearts can be changed, but Eve doesn't believe him.

They get into town and meet up with Jake in a bar, the Zanadew Lounge, where Santa reverts to his "Odin" reincarnation, drinking heavily and starting an enthusiastic bar fight with the locals, much to Jacob's delight. Unfortunately, when they finally get to the airport, they find that the pilot is gone because Ezekiel, in a fit of Christmas joy, sent him home to be with his fiancée. However, Santa claims that he can fly large objects through the air, so he pilots the plane towards the part of Alaska where the northern lights can be reached.

Unfortunately, Santa is starting to feel ill from the weight of the good will and the effects of the poison, and struggles to keep them on track. As they approach the Aurora Borealis, Dulaque and Lamia board the plane while it's still in flight using Santa's sleigh, which they stole. Dulaque makes a mock-attempt to get the Librarians to hand over Santa, ending with him simply saying that he's going to kill them. Santa passes out and Eve puts the plane on auto-pilot. She brings Santa back to the cargo area and finds that Lamia and Dulaque have subdued the other three. Dulaque informs her that he's poisoned Santa with holly and mistletoe, "old hedge magics", and says that Morgan Le Fay would be proud. He gets Lamia to disable the plane and prepares to kidnap Santa once more.

Eve tricks Dulaque into putting Santa's hat on, by letting him know that it's a magical talisman of power. The Librarians use the fact that the hat makes the wearer want to spread joy to others, telling Dulaque it would make them very happy if Lamia left, and he sends her away in the sleigh. However, Dulaque removes the hat when they try to get him to say how to stop the Brotherhood. Eve manages to kick him towards the cargo door, and grabs his hand, but Dulaque willingly lets himself out of Eve's grasp to fall out of the plane. The plane is struggling to stay up, but Eve manages to land it with some help from Jacob looking it up on Google.

They make their way to an abandoned but still working pipeline survey station, but find out that Santa's not up to the task of delivering the gift, due to his being poisoned. Although each of the Librarians offers to help, even knowing they might not survive the experience, Santa reveals to the group that Eve is tuned into Christmas because she was born on Christmas Eve--which is why she's named "Eve". Santa transfers all of humanity's good will to Eve and tasks her with delivering the "gift": all of humanity's good will, transformed into hope. She is transported magically throughout the world and helps countless people to save lives, be encouraged, and feel hope. When she comes to, she finds she has survived and all good will has been spread.

Jenkins lets Eve know that Dulaque will have survived falling out of the plane, as they're--himself and Dulaque--are much tougher than that. However, he also lets her know that Santa is making a full recovery.

Just as Eve says that her plans for the holiday are a little peace and quiet, Cassandra, Jacob, and Ezekiel surprise her with a birthday party, with a banner, cake, and presents. As they celebrate, they realize that each of them got what they'd wished for earlier: Cassandra gets to believe in Santa, while Jacob got his bar brawl, and Ezekiel got to be a good guy for a while, although he claims he hated it. When Cassandra says that it's too bad Eve didn't make a Christmas wish that would have come true, Eve just smiles.