Alt-Elizabeth - our Peter's mother - visits Walter, to convince him to try to help Peter get back to the world and people he loves. She forgives Walter for kidnapping Peter - in which her transformed alternate reality, Peter died as he and Walter were crossing the lake. And she convinces Walter.
A little later, when Walter comes to see Peter, it's clear that Peter is starting to feel a real connection to Walter. It may be that the main help that Walter can give Peter to get back "home" is getting Peter in touch with the fact, or, at least, almost fact, that Peter is home already.
Otherwise, I'm really enjoying the smooth way the alternate sets of characters relate to each in this new transformed double set of realities. Sitting across a table from one another, out in the field shooting bad guys, mixing Peter in as a a wild card who knows things that neither set of characters does, Fringe is giving us a wild and wildly believable and satisfying tableaux. Not easy to do even in a novel, let alone television show. Fringe is setting standards in complex story telling that we may not see again for years.
And the villain set is pretty impressive too. Alt-Broyles is a damned good, dangerous double agent. He's even got me wondering if he's somehow brought our straight-laced Broyles into his web. Alt-Broyles and his boss Jones make a powerful combination. And the revelation at the end that Jones is taking his orders from our (transformed original universe) Nina promises a tough fight even against the assembled intelligences of both Walters, Olivias, Lees, and Peter.
... Fringe 4.2: Better and Worse Selves ... Fringe 4.3: Sanity and Son ... Fringe 4.4: Peter's Back, Ectoplasm, and McLuhan ... Fringe 4.5: Double Return ... Fringe 4.6: Time Slips ... Fringe 4.7: The Invisible Man ... Fringe 4.8: The Ramifications of Transformed Alternate Realities