Why did Hiro have to bring Charlie back? isn't this supposed to change everything? and how is this gonna work back into the present now? so confused! and what's up with Noah and his "mystery" love affair with the woman...that part was totally pointless and has nothing to do with the plot of the story!

Why bring her back? It was Samuel who let Arnold bring her into present time, not Hiro. It is also Samuel's new butterfly theorie that allows selective changes...

i didn't care for that blonde woman, but i think her involvement in last night's episode has everything to do with the plot of the story, especially after last night.

and hiro saved charlie because it is part of his personal mission that he assigned himself at the beginning of the season.

I don't care about the whole Hiro and Charlie thing...it's a lil icky and besides what does Charlie has to offer? and how would she help in anyway...I mean all she knows is information about stuff but how is that gonna help anybody heal or help anyone survive..I don't think she has any important power...Jeremy had more to offer than Charlie...I don't care for her.

I'd like to answer this question, but there might be young people reading this! lol

This show is far from a ''there's the bad guys let's kick there a**'' thing. It's a lot about characters development and storyline. Hiro loves Charlie, that's more than reason enought to try and save her!

As for changing the timeline, that's what I personnally call the ''Time-Bottle Exception'', in reference to Samuel throwing the ball and dropping only one bottle, when he explained it at the beginning of the season. Basically, if you're careful and change only the right things, you're safe. Charlie's death had very few influence to the rest of the story, so saving her is not harmful to the space-time continuum. Every other characters' situation (Peter, Sylar, Nathan, Isaac, Eden, Noah, Claire, etc.) would be in the same situation wether Sylar killed Charlie or not, - him having good memory back in season 1.

That's probably more than enough there when coupled with the fact that she is Hiro's love. If it isn't useful here, then surely it can't be useful to Sylar either, so why does it matter whether he kills her... right?