Grey Matters
The First Wave breaks into a mental hospital and cures a long-term patient suffering from schizophrenia. When the Fringe team investigates, Olivia discovers that the group's leader has one of the heads stolen from cryogenic storage months earlier. Meanwhile, two…
Episodes
21
Northwest Passage 44
In Noyo County, Washington, Peter stumbles across a grisly murder with ties to Newton and First Wave. He is forced to team up with a suspicious sheriff to get to the heart of the case. Meanwhile, Walter has trouble functioning without Peter, and worries he will be sent back to the mental institute.
22
Over There (1) 44
When Walter discovers that Peter has traveled to the alternate universe, he and Olivia gather three cortexiphan children with the ability to transition safely between the two Earths.
23
Over There (2) 45
Walternate asks Peter to help complete the device, while the fugitives Walter and Olivia are reunited with William Bell. Meanwhile, the alternate world’s Fringe Division closes in on the invaders, and Peter must make a life-shattering decision.
