Fringe, Season 4

September:
In my desire to witness the moment, I inadvertently distracted him from discovering it.

Peter:
I already know all that. Walter told me, but what were you doing there?

September:
It was important. You are important. It was why I could not allow you to drown at the bottom of Reiden Lake. It was necessary to allow the other Dr. Bishop to cure you instead. Despite my efforts to set things right, these actions only culminated to further corruption of the timeline. The war between the two universes, drastically altered destinies, brought about a child that was not meant to be.

Peter:
What child?

September:
Your son: Henry.

Peter:
My what?

September:
He was born to the wrong Olivia Dunham, due to a series of circumstances that never should have happened. This event would have irrevocably altered everything that was to come.

Peter:
Henry. [smiles] I have a son.

September:
Had. When you made the sacrifice to step into that machine, you were not the only one that ceased to exist; so would he. I believed at the time that would be the end of it. I can't explain, but it is clear that I was wrong. You have managed to return to physical form. I suspect this will provide an opportunity to set things right. She is the one. The Olivia Dunham from whom your shared future was meant to spring. This must be, and everything will be as it was intended. You must find a way. [becomes distracted] They are coming. You need to go.

Peter:
What's happening?

September:
There is no time. I am going to need you to do something for me.

Peter:
I'm not doing anything until you tell me where to find Olivia.

September:
For that you have only to go home.