Everyone meets in DC, as the goals among Heroes include destroying Building 26 and ensuring that Sylar cannot shape shift into the President. As far as the second is concerned, a series of events lead Claire, Peter and Nathan to the building where the President is giving a speech. Nathan is able to convince his Chief of Staff that the President is in danger.
Later in the episode, after Sylar kills this same Chief of Staff and ends up - shape shifted as the Chief of Staff - in the limo with the President, he extends his hand. The President touches it - and pulls Sylar close! It's actually Peter, who had stolen Sylar's ability during an earlier fight and is now using it again him. Peter sticks Sylar in the neck with a tranquilizing syringe. There's just one problem:
In that same fight, Sylar had killed Nathan. Now, Parkman, Angela and HRG face a dilemma: as they stare at Nathan's dead body and the unconscious one of Sylar, they know there's only one way to get the government off their back: Nathan must be alive to speak to the President. After a bit of convincing, and inspired by making sure his family is healthy, Parkman goes to work:
He gets control of Sylar's mind and convinces him that Sylar is dead; he's really Nathan Petrelli. Sylar shape shifts and wakes up, supposedly implanted with all of Nathan's memories now.
As the episode draws to a close, all the main characters are around a fire, one that is burning an unsconscious Sylar to death. Of course, this isn't really Sylar's body, as the person that resembles - and acts like and thinks like - Nathan is truly Sylar. (Following along?) But only Angela, HRG and Parkman know this. Another thing to note, at this grand meeting of Heroes, is that Hiro is still facing nose bleeds as a result of his time stopping.
Volume four ends with everyone walking away fromt he fire that has consumed quasi Sylar. Then, volume five begins.
It's six weeks later. We see Tracey come to life and kill a former Building 26 agent, telling him he's number-four. Is she taking revenge on all that supposedly killed her before?
We then see Angela arrive at Nathan's office to take him to lunch. He's acting a bit strange. He walks over to a clock, says it's a minute-and-a-half fast, fixes it and then appears to be in a good mood. But Angela, and all viewers, are quite suspicious. Just how much of this indivual is Nathan and how much is - gulp! - Sylar?!
Source: TV Fanatic