In this episode, the Fringe team investigates a bizarre phenomenon when 15 people up and down the Eastern Seaboard all suffer retrograde amnesia from listening to their shortwave radios on the same frequency. Much to Walter's dismay, Peter presses on with piecing together the doomsday device. Just as Fauxlivia and Peter's chemistry deepens, the anticipation of Olivia's return escalates.
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This episode's glyphs spell:
The Observer can be seen standing in the crowd at the crime scene after Fauxlivia killed the Shapeshifter and threw him out of his apartment window.
The Franklin St. Station subway sign in 'Amber 31422' shows the numbers 6-9-5-5, foreshadowing the radio station frequency investigated in '6955 kHz'.
Unknown
In "The Day We Died" Peter explained that the Fringe team from 2026 sent the pieces of The Machine to the past, explaining how there could be technology broadcasting radio signals before the radio was invented.