From publisher blurb:
In Gathering the Magic, the characters learn about a strange outbreak of mimic, shape-shifting creatures that assail the region around a forest. They gather at the Drunk-Deer Tavern to learn about this situation. A local mage lets them know that there is a strange source of magic coming from the forest depths. It appears that the monsters are not related to a strange cult called 'The Gathering', which has risen to prominence in recent weeks as they attack merchant caravans.
The characters defeat the source of strange arcane energies in the forest and come across some cards that belong to the Deck of Many Things. It it then revealed that the Gathering has also been collecting these cards. The cult's leader has been able to siphon out the energy of the Jester card, gaining great power. The characters not only confront this cult, but they may also assemble the whole deck at the end of this adventure.
This is an adventure that takes the heroes to a mimic-infested cavern, pits them against cultists with access to advanced magic, and gives them the chance to assemble the Deck of Many Things and derail the campaign...