In the episode 'The Arrival', there was these foreshadowing dialogue:
"Have you never taken anything that doesn't belong to you because you knew it was the right thing to do?"
"This isn't about me."
"Perhaps it is Peter."
"You are sitting here. My son. Alive."
And in the season 1 finale ep 'There's More Than One of Everything.", Walter said this about the alternate universe: "Take from there, what I had lost here."
Real Peter died in 1985, Walter has referred to 1985 by saying "I was under a great deal of stress at the time." The mystery of how Walter stole Peter is yet to be answered. What about the car crash on the frozen lake? Who are the people following Peter? Why did Walter ask Olivia if she had seen Peter's medical records? Nina Sharp says she knew Peter when he was young, the question is which one? When Walter was back in the mental hospital, he saw visions of another malevolent looking Walter. Was this guilt over his actions or a hint that the other Walter wants his kid back? Then there is the fact Peter recalls his father shocking him with a car battery. Walter needs to grade his own parent paper.
All this is intriguing stuff. Walter never did think of the consequences of his actions. So what'll be the ultimate result of Walter stealing Peter? How will Peter react when he finds out? All I hope for is that season 2 of 'Fringe' does this storyline well. I mean how can TPTB screw up a storyline in which Walter stole Peter after the death of his original son? Is the other reality dealing with its unspecified chaos because of what Walter did? Walter created a 'plug' with the specific purpose of stopping someone coming through from the other reality. Was that someone the other Walter? Given the lengths Walter went to, to get his new son - what lengths would the other Walter go to to avenge the abduction of his son? All through season 1 it was obvious Walter crossed several ethical boundaries with no care for the consequences. Peter is often upset and angered by this. What will Peter do when he finds out that he himself was kidnapped by his father from the other reality? That in his grief Walter dragged him from his home, family and reality to be the replacement son? I can't wait to see this in season 2. (2018 update: TPTB RUINED this show and I deleted my Peter Bishop icon, screw TPTB)