From the website:
The world of Terra was forever altered when four of it’s six moons crashed into the planet, breaking apart and revealing their sources of magic, the Crystals. The magical energy of the Crystals bathed the world, giving skill and power to those who had never known it.
The four elements marked all living things. The Magma Crystal scorched the lands of Zeutenheim, but gave strength and resolve to it’s people. The Deep Crystal gave a bounty to the plains of Halleford, and gave life to magical creatures. The Iron Crystal sealed away the cities of the dwarves, but gave trolls the power to build their hero-testing dungeons. The Sky Crystal lifted a continent into the air and gave power to wizards, letting them cast spells alone, that they could never dream of casting in the cabals before the disaster.
The planet itself was polarized by the event, the magical draw of the Crystals keeps one side of the planet always facing its star. Despite the tragedy, the world moved on; knights defended castles, wizards researched spells, and trolls built dungeons.
Now, as the world has settled into it’s new order, one of the Crystals has fractured, and a sickening, corrupting miasma has spewed forth, altering any who touch it. A new war rises on this planet of Endless Day and Endless Night. Will your group be the heroes who save Terra?