6. Through the Looking Glass and What Walter Found There

Complete story — includes the ending

Having retrieved another tape from amber, Walter follows its instructions to a half-derelict apartment building that contains the entrance to a pocket universe where the normal laws of physics do not apply. He encounters a man called Cecil who was trapped in the pocket universe when breaking into an apartment. Olivia, Peter and Astrid follow Walter. Together, the team find out that Walter and Donald hid a boy from a previous Fringe case in the pocket universe. The boy is no longer there, but they find a radio that was apparently left there for them. Observers and Loyalists pursuing Walter catch up with the Fringe team, and a fight ensues. Cecil is killed by an Observer. Peter's new Observer implant enables him to fight the Observers effectively. However, he does not tell the rest of the team about the implant.