it takes place at 75 years into the future
Everybody from the first generation has died (which is Aang and his friends) and the next generation comes
75 years and they've only gone one generation further. The average life expectancy of people in the Avatar world must be a lot longer than one would expect in our world at the same level of civilization (I know that King Bumi would have been something along the lines of 110 or so in the orginal series, but I always thought him the exception in life span, not the rule. I suppose it is also likey that the 75 year thing only applies to the innner circle of our main characters, most of whom wind up in positions of priviliege living "the good life" so they may have lived longer than the normal for people in the world).
A part of me actually wanted the series to occur even further along the time line than this is, for the simple reason that I am curious as to how the Airbender writers are going to adress what I see as a major plot snag. As of the orginal series, Aang is the last Airbender, all the others were exterminated. So exactly what is going to happen in three generations, when the next Avatar to be born is supposed to be another Air bender. The only possible Airbenders left are going to be any children that Aang had and not all of them, some will presumably not be benders at all, and others will be water benders (assuming it was Katara he actually ended up marrying) Fire benders and Earth benders (depending on whom thier children marry). So the pool of candidates will be rather limited.
"For I have heard the Song of War, and to me, it sounds just like "Please, Mister Custer.""
Cogito Ergot Sum, "I think there is something wrong with this rye bread." (Aplogies to Seafrol.)