After watching yesterday's episode I think that Adam has been waiting for centuries to reach Hiro's time and destroy Hiro's reality.
Adam was most likely behind The Company to make them destroy New York with Hiro in it but the idea failed.
- What was the reason of destroying New York? How could he had assumed that Hiro would be in New York? He obviously knew the father was in New York
- Who released Adam? When was he captured? Maybe in the time between the bomb explosion and his appearance? Who had the power to capture him? Somebody must have a more cruel reason to have released him
- Who, how and why were Peter and Sylar rescued?
- Peter was in the Company's hand, did he had his memory there?
- Why Adam has contacted Peter? He is going to use him, what for?