Fringe: Season 2, Episode 5

2 - 5: Dream Logic

In Seattle a man attacks his boss believing he was a demon. Walter finds a computer chip attached to the thalamus, the part of the brain controlling dreams. Broyles and Sharp reveal new information leading to the sleep researcher who implanted the chips. Walter changes his theory; the dreams are being stolen from their hosts to cause a "high" in the researcher, who is receiving them, and has two personalities. His doctor personality sets a trap so that Olivia and Peter will catch his alternate persona. Meanwhile, Olivia is grieving for Charlie, whom she discovered was murdered by a shapeshifter in the previous episode, and Sam helps her work through it by reminding her of her and Charlie's first meeting.