I'd want something where you have not been trained in any specific class (warlock, titan, hunter) but you have some basic fighting skills (VERY basic). You have been traveling from a settlement camp far outside of the main city. You were staying with a group or survivors like yourself but the encampment was overrun by enemies. You were split off from the group and you are travelling alone (this is where the tutorial would take place, to get used to the controls etc). From here you keep traveling towards the city because you have heard about it as this safe haven from everything. Fighting very easy enemies along the way (and a whole lotta other stuff) you eventually reach the city, where an assault is being pressed against the front gates by a group of enemies you defend gate with Guardians of the city and eventually push back the assault. You meet the Mayor who recognised your amateur skills during the attack and decides to get you trained to defend the city properly. This is where you choose your class. He then directs you to a "Master" in the class you have chosen. He then teaches you the basics about your class. eventually you get known in the city (start doing quests, taking up jobs etc.) Then things pick up from there..... I may gotten a LITTLE carried away :D