Bold Adventurers the Fountain of Youth awaits your lips….
One day a you are walking on a road to get to a popular city of some sort. All of a sudden you encounter a group of bandits walking towards you looking to start a fight.
The Elven city of Pulca is under siege by a small chaos clan of beastmen. The General of the beastman is a shaman that is attempting to open a warp gate from the the Choas realm. If by any chance the gate is opened many many choatic deamons and abominations will be turned loose on the grand Elvish City of Pulca.
Real World: some Indians in the Amazon treat their eyes with a traditional potion applied with palm leaves. Brutally painful, the drug alters vision, giving the jungle's dense green walls greater texture and dimension. You could adapt this to desert or swamps, or other hard to navigate regions.