The "Fringe" episode "Black Blotter" was a brilliant look into the mind of Walter Bishop (John Noble) -- after he drops acid in an effort to remember his Plan to save the world from the Observers. The episode begins with a ominous, frightening sound. Then it switches to a "Twin Peaks"-esque series of odd visions, followed later by a "Monty Python"-style segment Walter must have dreamed up in order to remember his black umbrella. But more on that later. All this goes on while keeping up the eerie-creepy-scary factor (which "Fringe" shares with "Twin Peaks").
The weird signal
The team had found a radio in another episode, "Through the Looking Glass and What Walter Found There." It was pulled from an actual parallel pocket universe that really was "out of this world," with no drugs required. The radio begins letting out some strange sounds, waking Astrid (Jasika Nicole) from her slumber. She creeps out to the lab, where the spooky noise is coming from, only to find Walter having some sort of meltdown. Walter is completely useless to the team while he's in his own mind's pocket universe, on a type of acid he calls "black blotter," but his visions do teach the viewer quite a lot about things that happened long ago.
Anil (Shaun Smyth) comes to the lab in order to help the crew track the signal from the radio back to its source. The signal leads Peter (Joshua Jackson) and Olivia (Anna Torv) to an old grown-over van with a skeleton inside. There are also skeletons of two Observers and a Loyalist outside the van. They appear to have gone through at least 10 to 15 years of "decomp." Apparently, Donald -- the unseen man who had helped Walter in the pocket universe, but of whom Walter has no memory -- killed the bad guys to protect the signal, but died of wounds before he could escape in the van; except that it's not Donald. It's Sam Weiss, who existed in the original timeline (where Peter never stopped existing) and had knowledge of the Doomsday Device and the First People.
In the current timeline (where Peter was never born, a la "It's a Wonderful Life," but was somehow willed back into existence), Sam Weiss died not long after the Observers took over. As a man who knew a heck of a lot about the universe, his protection of the signal must be significant. The signal Sam Weiss was protecting was just a relay to boost the signal emanating from another location
The gang takes off together to find the source of the signal. In Walter's mind, however, Walter has betrayed his friends and joined the Observers, on a very "Twin Peaks"-style trip. An Observer walks up to open his cab door, but it's really just Astrid. One thing stands out during Walter's "trip," however: black umbrella. He has no idea what it means, just that it's in his head.
When the group finds the source of the signal (after a run-in with, and wiping out of, several Loyalists), they are greeted with a man and his rifle. The man is guarding a Child Observer (Rowan Longworth). The Child Observer steps out, but they can't have him until they say the password. Walter remembers "black umbrella" is the password, only after a Monty Python excursion, in which he takes a ride on Gene (Walter's cow) to meet his friends (depicted as a seahorse, dog, and frog). After a tree-key fight with a Walter-knight, he pulls his black umbrella from a tree trunk full of kids and is windblown (by a godly cloud-man) via that umbrella (Mary Poppins style), down a pipe, past the turkey-eating mouth sitting on Walter's face. Trippy.
The Child Observer
The Child Observer is supposed to be the most important key of The Plan to save the world. They have him now. Like his counterparts, he does not seem to show any emotion, other than what seemed to be a possible subtle smirk when Olivia offered him hot chocolate. That could just be a projection of a feeling person, however. We'll have to wait until the next episode to find out what part he plays in The Plan.
Will the real Walter please step off a cliff?
It becomes very clear why Walter is so afraid of becoming the man he once was, now that the pieces of his brain have been replaced. The Complete Walter is a man who wanted to destroy the world and create his own from scratch. Complete Walter is evil. Incomplete Walter is kind and gentle. He is afraid of his old lab assistant, Dr. Warren (Jenni Blong), who warns him of the danger he poses throughout his "trip." "Trip Nina" (Blair Brown) coaxes Walter through the process of finding the signal and "saving the world," while "trip Dr. Warren" (who had died in a fire while trying to destroy Walter's life's work) tries to convince him it's too late.
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