This week on Fringe, Astrid is woken up in the middle of the night by the radio from the pocket universe finally picking up a signal. She is startled by Walter, who not only remembers her name but thinks her hair is beautiful. Obviously, Walter is not quite himself.
Peter, who is disappointingly normal again after removing the Observer device from his head, also wakes up. They quickly determine that Walter dropped a little acid of the Black Blotter variety and is busily tripping away. He is immersed in visions of his former lab assistant, Carla Warren, who is busily berating him for the man he used to be and who he really still is. "You were him longer than you've been you" she repeatedly tells him. Walter tells Peter that Nina promised to remove the old pieces of his brain, but only after he remembers the plan to defeat the Observers. He thought the acid would help him access "the Walter that was" so he could remember what the plan was.
Olivia decides that they need to try to triangulate the signal, and hopefully find the mysterious Donald. Meanwhile, Walter lays down and talks to his new little green fairy friend, who is shortly joined by a little red fairy. Carla continues to drop ominous hints about what is hidden in the lab. Anil shows up and helps to locate the origin of the signal in Connecticut, so Peter and Olivia head out. Peter uses this alone time to apologize for being a jerk and sticking questionable objects in his head. Right when they get all cuddly, Olivia notices an old van and some old corpses. The bodies were of some Observers and another body in the van turns out to be Sam Weiss. You remember Sam from the bowling alley don't you? It looks like he died 10 or 15 years ago trying to protect the transmitter for the radio signal. Yes, the transmitter. They haven't found the origin of the signal, just a relay to boost it.
Back at Harvard, Carla has Walter playing a game of Hot and Cold, looking for what is hidden in the lab. She lectures Walter about what an egotistical ass he was. Seriously, this hallucination has some serious evil qualities. As he finds the hidey hole, a much younger hallucinatory Nina appears warning him to stay away from it. Carla whispers that it's his life's work, all his secrets. She died trying to burn it when the lab caught fire around her. Walter can't resist the temptation and shoos the green fairy away and opens the book. He is busy looking through his book in a taxi continuing to argue with Carla over who he used to be when the words "black umbrella" pop into his head. Carla declines to tell him what it means. He comes to himself with the others renting a boat to find the origin point of the signal. The signal is coming from an island, which Walter sees as the Emerald Palace from the Wizard of Oz. Just as they are about to board the boat, some Loyalists arrive and they have to fight their way free. While Peter has lost his Matrix moves, he can still kick ass at least.
On the island, Carla continues to glare ominously at Walter. The group finally comes to a house. The man there appears to recognize Donald's name, but refuses to put his gun away. Suddenly, the child Observer comes out of the house. They explain the situation to Richard and Caroline, but Richard demands the password. This prompts the single most terrifying scene in Fringe history: Walter embarks on an epic Monty Pythonesque cartoon quest in which he must defeat the “Walter that was” for the key to unlock his memory. When he emerges, he blurts out "black umbrella". In that case, Caroline invites them into the house. The green fairy promptly applauds this accomplishment and Walter throws her a shy smile. It appears that the couple were early members of the Resistance. Donald left the child Observer with them about 8 months after the invasion and they have never heard from him again. They named the boy Michael. He has never aged a day in all these years and never spoken. The couple tearfully bundle Michael up and say goodbye as the team takes him away. Back at Harvard, Olivia brings the boy some hot cocoa. She tells him a little about her little girl and then asks him if he remembers her. He slowly nods his head. Apparently even though he met Olivia in a completely different timeline, he still remembers her.
Walter sits alone in the dark and sorts back through his memories of his greatest failure and success; his doorway into the alternate universe. "I have become Death, destroyer of worlds." Ah, Oppenheimer. He decides to destroy the journal. He places it in a dish and sets it on fire, only to discover that it never existed. It was just a hallucination representing all his former knowledge. "You've been him longer than you've been you" Carla whispers as she fades away. When Walter looks up, he is facing himself through the flames.
The next episode of Fringe, "Anomaly XB-6783746" airs Friday, Dec. 21 at 9 p.m. EST on FOX.