All five of the primary Fringe Division members face-off against the invading Observers in a complex and extraordinary battle to manipulate the fate of mankind by altering future events and deflecting history away from the path to total oppression.
This episode's glyphs spell:
This episode brings the story of Fringe to a close.
Observers are featured in this episode.
Signage on the dock in 'Liberty' shows an image of a man putting a finger to his lips (to say 'quiet'), foreshadowing Michael giving the same gesture to Olivia in 'An Enemy of Fate' when she asked him what they have to do next and when she killed Windmark.
In "An Enemy of Fate" the Fringe team successfully changed the future so that Observers would never be created.