December is shaping up to be quite busy, so I suspect I won't have an opportunity to use these, but you might! Here are two Troika! adventure hooks for Yuletide:
Dead Letter
Centuries ago, a delivery meant for Santa's workshop arrived at Whalgravaak's warehouse instead, and Santa's elves only just tracked it down. Can you retrieve the parcel from its resting place?
I haven't decided where to put Santa's misplaced package, but Rooms 12, 13, 14, or 15 all seem like potentially good resting places.
Kidnap the Sandy Claws
Can you help? Rudolph approaches the player characters, having wriggled free from his harness. Santa entered a building to deliver packages hours ago, and hasn't returned! Can you rescue him?
Santa has been kidnapped by a gang of cocksure gamins (as described in Get It At Sutlers, page 67) who seek to use his intended presents for their own pleasure. If you're stuck for a hideout location, I might start with Dyson Logos' South Sewers Hideout, stocking it with gamins, guard animals, sewer monsters, and a beefy lad to act as the local boss. (I might go with the stats of an ogre from the core rulebook.)