Not much happened. Except Hiro discovering something we all knew for like 4 episodes: that Arthur is alive. Big fucking whoop.
And as far as filling in the holes...it just made the universe feel SOOO small.
Claire with ANOTHER uncle?
Her mom was the cause of the train fire?
Elle and HRG made Sylar go bad? (which is INCREDIBLY lame.)
And of course as soon as Arthur said, Well, I guess Nathan is going to have to die, I was WAY ahead of them with the car wreck.
This is what I would call a pot (not plot) filling episode. Needless things answered, that really weren't questions.
We are more than half way through this volume and not much has happened besides little things. It's been about the villians getting together....it's a 12 episode ORIGIN story.
And hell, this episode didn't need Hiro as a framing device AT ALL.
Basically, it was an hour of exposition...for stuff that happened TWO YEARS ago. It doesn't add to the CURRENT story...not that there's much going on with that.
Thank god they've fired some of the producers, perhaps there is hope for the next volume.