In Tales of Vesperia's world, "rings" made up of a substance called "blastia" protect the cities from monsters. Therefore, most of the villagers who live in the cities never leave their place of birth. However, those "rings" are breaking down, causing more monsters to be born...

The protagonist, Yuri, used to be a military knight, so he's seen some of the world. The antagonist (supposedly), Flynn, regularly journeys outside of the city, battling monsters and seeing the sights. Flynn decides to leave the city, and Yuri becomes envious of that, deciding to do the same...