Skies of Arcadia is an RPG from Sega. In the game you control a Blue Rogue pirate named Vyse. Along with Aika, Vyses childhood friend, and Fina, a mysterious girl that Vyse and Fina found on one fo their journeys, you start upon an epic journey.
Fina, is looking for these things called moonstone crystals. These crystals have a special power that allows whoever posseses them to be able to control a Giga. A Giga is a superweapon that can cause such massive destruction that at one point in time in the history of Arcadia they almost ccaused the destruction of most the world.
Fina is not the only one looking for these crystals however, the Valuan Empire is also searching for them. Valua wants to control the Gigas so that they can use them along with thier extensive armada to take over the world.
The stage is set, it's time to see what you're made of. Take out Valua or lose your freedom!