Fringe

Pay attention, people, here's where it gets interesting.

Olivia wakes up in William Bell's office.  He is pleased to see her and tries to establish a friendly tone by reminding her that they knew each other well when she was a child.  He talks about the other children he experimented on.  Olivia knows about them; she is pretty much the sole survivor.  Bell isn't surprised.  He says she was always the strongest of the experimentees. She doesn't want to hear it; she wants answers. 

Olivia is disorientated throughout the entire   meeting.  Her memories seem to jump; she can't recall the whole conversation.  It is full of holes.  Bell tells her that the disorientation is due to the time slip.  (Ha!  I was right.  There is a time dimension shift when you cross over to the other side.) 

Bell tells her that someone was trying to prevent their meeting.  He brought her to the other side for a particular purpose.

He has seen history repeat itself often enough to know that a storm is coming.  He can count on one hand the number of people who can safely travel between the worlds.  But the other side has created hybrids, spies to send on ahead while they are trying to perfect a way for normals to cross.  The shapeshifters are simply the first wave.  Bell tells Olivia that he has chosen her to guard the gate.  The shapeshifter on the other side have found someone who can open the door.  She has to stop them.  He shows her a symbol will identify their leader.  She is supposed to show it to Nina Sharp because he can't go back yet. 

As he prepares to send her back, he warns her that he pulled her from a moving car.  Momentum must be maintained.  And because physics is a bitch, it is really going to hurt when he sends her back.  He rings a bell on his desk.  And we all know how that worked out for her.