On December fifth in the late 1800s, William walks the streets of New York, full of Yuletide cheer, to visit his friend Augustus. He passes violently boiled carolers and smiles, for he knows his friend is home for the evening. Augustus greets William's knocking with a sword through the mail slot, but upon realizing he is being visited by a friend and not more wretched singers, he lets him inside. Finally! Another member of the White Street Society is here to help him!
Augustus loathes Christmas and all those who celebrate. He fears the great Sinterklaas who drives a sleigh pulled by flying hellbeasts, sneaks into homes like a murderer, and judges based on no good reason who is naughty or nice. He's a vile monster who has a terrible infatuation with children. Before Augustus can continue his Santa rant, there is a knocking at the door. Thinking it to be more carolers, Augustus suggests William answer the door with a revolver.
It's not carolers though, it is a charming German woman named Greta von Hitler and William is immediately smitten. Augustus, however, immediately bashes her on the head with the hilt of a sword. When she awakens, she says she is seeking aid from Augustus and the White Street Society, for every year on December fifth, some of her orphans are taken from the German Kinder Orphanage for Forgettable Children and she is desperate to stop it from happening this year. Since they are only orphans, the police will not help, so here she is, asking for Augustus, and William because he is also there, to keep watch over the orphans for one night and to stop what's coming for them.
After some pleading by a still-smitten William, Augustus agrees to assist rather than remain alone in his house with carolers lurking outside. He grabs a pair of pistols with detachable Bowie knives, a sword cane, a pistol cane, a harpoon cane, a small harmonica gun, a five-barrel pepperbox pistol, a folding dirk, a short dagger, a poisoned needle concealed in a garnet ring, a garrote concealed in a watch chain, matching bottles of sleeping draught and poison, a knife-pistol, a pistol-knife, and a knife-pistol-knife and they head out into the streets full of rowdy revelers.
After passing through much merriment and into Kleindeutschland, they arrive at the German Kinder Orphanage for Forgettable Children. Upon entering, they meet Miss Goering, the old administratrix of the Orphanage. She tells them that these kidnappings have been happening for fifteen years, always on December fifth. Augustus surmises this is because the evil Sinterklaas's great feast is the following day or that this frau has brought evil with her from her homeland. He plans to stop Saint Nicholas and heal the wound he has brought about with his festering corruption. They will investigate the place where they store their orphans and see what happens overnight.
With the children sleeping in a different room, Augustus and William begin their watch over their bedchambers, leaving the fire burning low just in case someone happens to come down the chimney. Miss von Hitler brings coffee sometime later and while William is swooning at her in the hallway as she tries desperately to get away from him, a gunshot rings from the children's' room. Augustus has shot Father Christmas with his knife-pistol-knife and stabbed him. Twice. They have slain a beloved Christmas figure! They realize they will be in a bit of trouble when the orphans come to retrieve their gifts and find a murdered Santa on the floor.
To cover for this terrible deed, Augustus and William throw knives and guns out the window to attract the attention of an urchin boy whom they pay to go to the local theater and retrieve an actor they will make this evening's new Santa. They peel off Saint Nick's bloody suit and skin him of his beard and hair and get the actor, who is completely drunk, dressed and ready for his part, shoving him up the chimney to hide until it is time to come down and give presents to the children. They cut up the actual Saint Nick's body, hide the parts around the room and prepare to leave, their job well done. Then they hear the screams of Miss von Hitler.
When they reach her, they find she is screaming because Krampus has entered the room where the children are sleeping and is bashing them with a length of chain and trying to shove one inside a grisly kangaroo-like pouch in his belly. Augustus tries to shoot the Krampus with one of his many pistols, but the bullets do no good. William grabs a fireplace poker and begins bashing the Krampus into a pulp. Augustus joins in and sometime later, the Krampus is nothing but a boneless pile of wet carpet. Success!
Augustus, full of good cheer now that he's murdered two vile fiends, leads the terrified children into the kitchen for a cup of cocoa. While he's away, William, covered head to toe in Krampus-gore, tries to earn a kiss from Miss von Hitler, but she tells him she wants him to go. Augustus returns then, telling Miss von Hitler the children will have a nice surprise when they wake the next day which will erase this terrible night from their minds. They will be visited by the drunken actor Santa Claus and all will be well. Then, the two gentlemen leave the Orphanage.
William and Augustus talk of how excited the children will be when they wake to see Santa has visited, unless of course their drunken stand in wakes them first. Not to worry, though! Augustus kindly filled their cocoa with sleeping draught! Except... the empty bottle he pulls out of his pocket ISN'T the sleeping draught... Augustus has just poisoned all the orphans to death. Well, at least they're only orphans! They don't count as people!
The next day as William is convincing himself to take Augustus and turn themselves in, he sees an article in a newspaper about the orphan slaughter and sees that their drunken actor Santa was arrested for the crime. Oh no, they must tell someone! Then they find out that after a brawl in the street, lots of others were arrested and released and the drunken Santa was accidentally released as well! And now, he's on his way to South America to start a play called The Dogs of Shakespeare. Well, isn't that nice?
There is another article in a different paper that's even better. One of the orphans in the massacre was heir to a massive fortune and his uncle has left a great sum of money to the Orphanage in his honor. Now Miss von Hitler can expand her collection of orphans! All of this truly is a Christmas miracle.