The ancient trees weep black water and the fey roads have gone dark — something has torn open the boundary between worlds.
The Mirewood was a semi-sacred forest — old enough that even the elves had only fragmentary records of its founding fey compact. The compact bound a powerful Archfey called the Verdant Warden to the forest in exchange for its protection: the Warden kept the forest healthy and in balance; the forest served as a living anchor preventing the more chaotic parts of the Feywild from bleeding into the material plane.
Six months ago, a group of desperate miners — fleeing debt and a collapsing mine operation — broke into the forest's deep interior looking for rare mineral deposits. They found the anchor stone of the original compact, mistook it for an ordinary gem deposit, and mined out a significant portion of it. The partial destruction destabilised the compact without fully breaking it, trapping the Warden in a half-state: present enough to be corrupted by the leaking Feywild energy, but unable to heal or leave.
The black water seeping from the trees is the Feywild bleeding in. The madness in the animals is the Warden's corrupted influence spreading outward as it loses control. And deep in the drowned heart of the forest, the anchor stone still exists — cracked, partially mined away, but potentially repairable if the party can find the right material and navigate the increasingly hostile wilderness to reach it.
The original compact between the Mirewood and the Verdant Warden was sealed two thousand years ago by a grove of Treants who no longer exist. The documentation is fragmentary — the best record is a partial transcript held in a monastery at the forest's edge, which the party can find in the first act. The compact's key clause: if the anchor stone is significantly damaged, the Warden's essence becomes unmoored from its protective purpose and begins absorbing the chaos it was meant to contain.
The miners are long gone — some fled, some went mad from prolonged exposure to the leaking Feywild energy, and two simply vanished. One survivor, a former foreman named Brek, is living in the edge village of Ashfen, racked with guilt and barely coherent. He knows where the mining site was. He refuses to go back. He can draw a rough map of the deep forest if shown enough compassion — or enough gold.
The Verdant Warden is not a monster, not in origin. It is a being of profound grief, watching its purpose corrupt and its beloved forest die around it. If the party can communicate with it rather than simply surviving it, there is a path to healing. If they cannot, the only option is destruction — which will delay the curse spreading but not stop it, and may collapse the fey boundary entirely.