Maybe my favorite Fringe episode so far. It wasn't just a "victim has spooky death, investigation follows" episode. With Christine and the Observer it had likable characters that made you wonder what was going on AND care for them. And Olivia had time to show some emotions too, while Walter was being his regular awesome self (milk shake ).
Loved the whole "Obs have been around for ages" thing.

So...Observers saved Walter and Peter 20something years ago at a frozen lake. What more do we already know about this? Walter surely knows quite a lot about our bald friends. Maybe Peter is not from the mirror-verse but, like Christine in this episode, became "important" because an Observer died for him, just like the one did for Christine. Maybe Peter is "saved".

What I didn't get was why the assassin's ammo hurt and ultimately killed the Obs when the guard's in the beginning didn't.

Also, why was the Observer handed that suitcase in the "human bombs" episode a few weeks ago? They are neutral or, in best case, even helpful guys.

I am excited how this will develop, especially since the Obs see hard times ahead of Olivia.