Baten Kaitos Origins is a prequel to Baten Kaitos: Eternal Wings and the Lost Ocean, a Gamecube exclusive title released in 2004. The plot revolves around a group of characters who are struggling to discover the source of frightening changes (both natural and political) that are occurring in their world. During their journey, they will learn many details and help flesh out the first game- including how the despotic Empire government came to be.
In the initial stages, your party will progress in a linear fashion, moving from one area to the next along a set path. After you play the game for a while, you'll acquire a ship that lets you visit areas in the order of your choosing, allowing you to either pursue optional side-quests or blast through the main mission as you see fit.