In the third season finale, Peter (Joshua Jackson) was erased from history by a mysterious time paradox.
"Rest assured we won't betray the audience," Pinkner told TV Line. "Taking Peter out of the story is another way to look at our series from another side. [We'll examine] what would have happened in these people's lives up to this point if [there was] no Peter."
In the original timeline, Peter's mother Elizabeth (Orla Brady) committed suicide when her son was a young boy.
"[Whether Elizabeth now survived is] the right question to ask," Pinkner explained. "And that's what [next] season will answer."
Pinkner recently promised that unresolved issues from the season finale will be dealt with in future episodes, while Joshua Jackson suggested that the fourth run of Fringe could introduce "radical" changes.
Fringe will return to Fridays at 9/8c in the fall on Fox.
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