Written by Kinoko Nasu.
'Tis the season, and Chaldea is decked out in full Christmas regalia. While admiring the decorations, Mash notices that the protagonist has suddenly disappeared without a trace. Suspecting foul play, she rushes off to get Dr. Roman.
The protagonist awakens to a snow-covered field. They are quickly approached by Santa Alter, an Altria Pendragon Alter who has swapped out her armor for a mini-skirt and Christmas-themed clothes, and has certainly not been brooding over being defeated at a certain flame-engulfed city a while back. Altria Alter has suddenly gotten the urge to distribute presents like Santa Claus, but finds herself without any form of transportation after her previous reindeer ran off, so she summoned the protagonist to shanghai them into the role. While talking, they are set upon by Reindeer Men, attracted by her presents. Once they have been driven off, Santa Alter reaffirms the protagonist's status as her reindeer, and they fly off to deliver presents.
The first letter that they receive is from Darius, age 3, but the writing is smudged to the point of illegibility. Undeterred, Santa Alter is certain that she'll know what he wants when she sees him and flies off to his home. Accompanying Darius is Lu Bu and The Phantom of the Opera, who is lamenting about how Christmas is a time for lovers while he and his associates are alone. Santa Alter is moved by Phantom's passion, but the Assassin is enraged by her appearance and attacks along with Lu Bu. Darius charges in as well, excited for presents. After the battle, Santa Alter chastises them for their behaviour, she gives them their presents. For the two Berserkers, she provides each of them with a copy of Dragon's Meridian
Craft Essence; Phantom receives an Angel's Song
, which he mistakes for his beloved Christine. Their work complete, Santa Alter and her reindeer depart to fulfill their next letter.
Before reading the next letter, Santa Alter gives the protagonist a brief history lesson about Christmas. While it is now celebrated on the 25th of December, it used to be a celebration lasting several days, reaching its peak on the 25th. This is why the event takes place throughout the week preceding the holiday. The second letter is from a French girl named Marie, who is asking for a gift to bring together her two quarreling friends. Santa Alter scoffs at this, saying that Marie should be dealing with it herself asking for gifts for her, not for other people. If pressed, she'll say that she's in the business of giving presents, not happiness; any happiness derived depends on whether the recipient of the gift in question has been good or not. While still in the air above France, they are confronted by Astolfo. After trading some words, it turns out that he's merely acting as a spotter, and they are promptly shot down. On the ground, they are confronted by Marie Antoinette and Chevalier d'Eon, who are not happy to see them. After the fight, which Astolfo missed, it turns out that they had mistaken Santa Alter for someone else. The misunderstanding resolved, Santa Alter distributes her presents. Marie gets a Sorcery Ore
, which she fawns over, while d'Eon is less enthused to receive his Maid in Halloween
, and the implications therein. Astolfo is eagerly awaiting his gift, but Santa Alter abruptly leaves, saying that he does not get a present due to his absence in the Orleans Singularity. While he pouts over it, he gets knocked on the head by a Jack-o'-lantern
. He gets excited over it, while d'Eon and Marie are skeptical about what it represents.
Santa Alter arrives at the cave from which the third letter was sent, from an assassin apparently named "Jean Kay". She and the protagonist walk in to find Saint Martha pounding a sandbag, expressing frustration over how Christmas is celebrated in the modern day. Ushiwakamaru is also there, musing to herself about how her brother and her Master didn't want the severed heads of their enemies for Christmas. After noticing Santa Alter and the protagonist, Martha awkwardly welcomes them, while Santa Alter asks for "Jean Kay". Jing Ke does arrive at that moment, completely hammered, thanks to a traumatic event from ten days ago, according to Ushiwakamaru. Santa Alter offers to cheer her up with her present, but announcing herself as Santa causes all three cave-dwelling girls to turn hostile. After defeating them, Santa Alter asks why they've got it out for Santa Claus. They explain that a different Santa appeared, and conned them out of their money and belongings. Santa Alter is appalled, but proceeds to give the three their presents. Ushiwakamaru receives And So The Ship Conquers
, but isn't sure what to do with it. By contrast, Martha is more enthused by her Steel Training
, though she denies it immediately. Jing Ke, meanwhile, is given a Be Elegant
... and thoroughly enjoys it, declaring her intent to drunkenly assassinate the bearded man on the CE (Tokiomi Tohsaka). Her job done, Santa Alter takes the protagonist and leaves, leaving Martha and Ushiwakamaru wondering why their Master was wearing a reindeer costume.
Out in the middle of the ocean, Emiya and Robin Hood were having a fishing contest, but unfortunately, David snuck onto their boat and sailed into a storm while looking for women to woo. Tensions are high, and it looks like David may have to fight for his right to survive... and then Santa Alter arrives, and chides the three for their behavior. David once again ruins the moment by trying to hit on Santa Alter, causing her to challenge him to a fight to prove if he indeed is the "Most Victorious King". David requests help from his rivals, who agree on the basis of escaping the storm on Santa Alter's sleigh and believing they have a class advantage over her. As Santa Alter is a Rider, not a Saber, all three Archers are defeated. The storm clears after the fight, as do all moods, and Emiya and David learn that Robin Hood wrote the letter that drew Santa Alter to their location. Santa Alter gives the three Archers different
Black
Keys
each, as a hold over until their real present arrives... which turns out to be Elisabeth, and a Christmas concert. Leaving the three Archers at the mercy of a Lancer with an AOE Noble Phantasm, Santa Alter and the protagonist check the next letter, whose return address reveals its sender as Gilgamesh.
Arriving at Gilgamesh's castle, the protagonist and Santa Alter overhear his intentions to force Santa Alter to become his, and his inability to comprehend that it will never happen. Leaving Gilgamesh to wait for a present that will never arrive, Santa Alter and the protagonist opt to take the night off, but are suddenly caught in Nursery Rhyme's Reality Marble. There, they encounter Alice and Jack, two lonely children who wish for a warm Christmas. Santa Alter claims she cannot give presents to those who did not write her letters, but orders the two young girls to have courage, and try to take Christmas for themselves. Though Jack and Alice lose the ensuing battle, Santa Alter fakes defeat and creates Christmas decorations for them, and a Lightning Reindeer
to top it off. Jack and Alice thank Santa Alter, mentioning that the real Santa did come like the fake Santa told them. Once in the sky, Santa Alter notes that she can no longer ignore the fake Santa, and sets course to confront them.
The fake Santa turns out to be Caesar. He excuses his actions as the result of being mistaken for Santa by Darius while having no presents to give to anyone, only for his resulting lies to snowball from there. Santa Alter isn't impressed, and it soon becomes apparent that Caesar is enjoying the havoc he caused. With his real intentions out in the open, Caesar tries to usurp Santa Alter from the role as Santa. Though he's defeated, his surprising agility allows him to avoid Santa Alter's wrath, and he escapes into the night to hide from her. With the fake Santa problem solved, Santa Alter turns to the protagonist and reveals the last letter.
The last letter is from an Alter Servant, asking for a fun board game, specifically Monopoly. Santa Alter claims they must now confront a Servant who would desire such a thing as sadistically as possible. True enough, Jeanne Alter is not happy to see her, though she's surprised to see the protagonist as well. The two Alters start trading barbs, until Jeanne Alter questions Santa Alter's validity as Santa. Santa Alter admits that she took the job specifically to throw a present at Jeanne Alter, but enjoyed it more than she could've predicted. The elaborate prank revealed, Jeanne Alter counters Santa Alter with the revelation that, contrary to the blackened Santa's thoughts, Jeanne Alter isn't alone on Christmas. She's captured seven Pierre Cauchon ghosts and is forcing them to play Monopoly. The two Alters' argument turns physical, but Jeanne Alter and her ghost slaves are defeated. Despite this, Jeanne Alter isn't fazed until Santa Alter gives her the present— a Holy Night Sign
. Her pride crushed, Jeanne Alter resolves to train her Spirit Origin and be summoned to oppose her Holy counterpart. She leaves, dragging the unfortunate Pierre ghosts with her.
Their job done, Santa Alter thanks the protagonist for their help. Though the protagonist misses the point of her feelings, Santa Alter accepts them as her Master and knights them in gratitude. And so Santa Alter delivers her last present— her own Spirit Origin, to the protagonist. Affirming that she will now fight by their side, Santa Alter bids them farewell and a merry Christmas.
The protagonist is found by Mash in an unoccupied bathroom in Chaldea. She and Dr. Roman are relieved that they've reappeared just in time for the Christmas party. Though tired, the protagonist joins them, promising a funny story later.
Tropes:
- Debut Queue: Nursery Rhyme and Jack the Ripper make their debut appear as two of Santa Alter's beneficiaries.
- Early-Bird Cameo: Astolfo appears in this event's story several months before he is playable.
- Going Through the Motions: At one point Martha claims not to have her staff, while using her normal talksprite which shows the staff rather prominently.
- What the Hell, Hero?: Astolfo gets reprimanded for not showing up to defend his own homeland in the Orleans Singularity.
