From the introduction:
After surreptitiously infecting a community of Arbonesse elves with a magical scepter’s magic, the twisted elf Elela Sheleoss remained nearby until the elves succumb to the fungal rot she had conjured. Disappointed when the first casualties transformed into shambling plant creatures that followed her around, she decided she needed a place to study the scepter and further unlock its magic.
Unknowingly led to a clearing with a thinning border to the Plane of Shadow, she used the scepter to create a modest garden of fungi. As she grew more confident with thescepter, she devastated other small communities, which fell to virulent fungal infections inflicted by the scepter. Finally,
she nearly depleted the scepter’s power to create her grand Fungal Citadel, which stands as a blight in the forest and a beacon to her “converts.”
Surviving Arbonesse elves watch helplessly as their loved ones die and arise the next morning to shamble mindlessly deep within the forest toward the citadel. Aware of their susceptibility to the so-called Mushroom Queen’s magic, they seek outside assistance to defeat the menace.
This wilderness adventure for the 5th Edition of the world’s first RPG is meant for four 6th-level characters, and can be played as a followup to “Wrath of the Bramble King” or on its own.