Arye Gross guest stars as the scientist who created the new shape shifting technique.
The shifter uses him to perfect his product so that an army of shifters can invade our universe.
Walter struggles with the reappearance of Peter and considers it a great punishment.
Nina tries to talk Walter into accepting Peter as another chance to do the right thing with his son.
Olivia still isn't moved by Peter, and asks Lincoln out for a bite.