100 years ago the Life Tree died and the elves began to die. Brimhil, the eternally youthful queen of the elves, gave up her youth to revive the Tree. 100 years later, in the present, elves are being mistreated by humans and a half-elf Francis De La Cross attempts to obtain the power of the god-like creature to turn the tables and restore Brimhil's youth before she dies.
A young knight named Sir Lloyd von Roiental is transporting a holy staff known as the Wand of Kinan. He is ambushed and the staff is stolen by Francis, and Lloyd goes off to recover it. Along the way, he is joined by several other people who join his quest for different reasons.
Source: Wikipedia, "Astonishia Story", available under the CC-BY-SA License.