When a perfectly healthy woman is found dead from a disease she never had, the Fringe team investigates the origin of this inexplicably fatal condition before it claims more innocent victims. Meanwhile, Olivia struggles to keep Walter's secret from Peter, and her loyalty to Peter is tested as time goes on.
This episode's glyphs spell:
Walter described the actions done by James Heath as an exchange of energy between two people.
The Observer can be seen walking in front of Miranda Greene's car just before her skin breaks out.
Two Observers in 'Peter' exit a movie theater displaying a poster for "Clue", foreshadowing the title of 'Olivia. In the Lab. With the Revolver' and the confrontation between Olivia and James Heath.
Olivia's sleepless night in 'Olivia. In the Lab. With the Revolver.' ends at 5:18. May 18th (5/18) is the destination date of Alistair Peck's time travel attempts in 'White Tulip'.
Olivia did the same, subconsciously, as another Cortexiphan subject herself.
In Olivia's mind in "Lysergic Acid Diethylamide", Nina was outwardly friendly but had murderous intentions when she tried to push Walter down an elevator shaft. (Image 1)