You are traveling with your mom, when you are attacked by Viking pirates. In trying to find your mother you get involved in the Viking Invasion of Britain. Only really major choice is what side to support. Other than that there are loads of other choices to make which start with picking your character. These more minor choices do not change the main storyline but effect who you will play it. And, to an extent who will be your friends. There is also one major side story, completely outside the main storyline.