Some games like to hold your hand, slowly introducing you to the interface and the options and the story. A subset of these games go far past the hand-holding-during-training phase, they tell you quite specifically that you need to head from point A to point B and then on to point C, making the path obvious, the deviations minimal, and that set of goals the only ones worth your time. Two Worlds II isn't one of those titles. Not even close.
A truly massive open world RPG, Two Worlds II does have a basic introductory mission that it sends you on so that you get a feel for the title, but it barely scratches the surface in terms of what's available and how the game will actually unfold. As you run through this intro mission you'll be picking up book after book after book which you then have to read so that you know how to manage your skill your tree; craft weapons, spells, armor, and clothes; and handle all the other various elements in the game.
Starting from the top, this sequel picks up immediately after the events of 2007's Two Worlds, with you (as "The Hero") and your sister being held by the Dark Lord Gandohar who still kind of wants to rule all of creation and have ultimate control over the dark powers. Gandohar would be, to use Buffy parlance, the Big Bad. The game opens with some nice Orcs (whom you as The Hero didn't really like in the last title) rescuing you from Gandohar's clutches, but not freeing your sister. So, your overarching goals in this game are to get back your sister, find Gandohar's weak spot, and bring an end to Dark Lord.
It is a pretty generic and not completely impressive story, but it quickly falls by the wayside once you finish the prologue and get sent off on your own. At that moment, the sheer size of the world you're in becomes apparent (the original also featured a massive world) and the number of sidequests and diversions proves staggering. As you wander around the world you can quickly lose the main narrative thread (which is made all the easier by the fact that it really isn't that great to begin with) and join guilds, battle bad guys, invest in the economy, find secrets, slay wild animals, and do just about anything else you might want (but don't swim too far out to see, because even if you think you're getting close to the next landmass you still might drown…. trust me).