The short begins as Pinky is listening to a parody of "I Am the Walrus," filled with even more nonsense lyrics than the original. He's also gazing at a magazine that has what looks to be pictures of all four Beatles from that time period.
The Brain tells Pinky to turn the racket down as he can't hear himself think. He's invented the lava lamp, though this variety overflows and holds you in place while you stare it, thereby allowing Brain to take over the world. He needs a large amount of sandal root to carry out this plan, which he tells Pinky can only be found in India. He says they will travel there the fastest way possible. "By yellow submarine?" Pinky asks. Nope, they're going by mail. That's the advantage of being mice. Pinky sings a line of a parody of "Magical Mystery Tour" before getting in the box with Brain. This version of the Beatles, by the way, are called the Feebles.
Once they arrive in New Delhi, they see a man buying the last bit of sandal root from a dealer because he's going to see the guru. They follow him to the Maharishi, but the Maharishi is gone. When the man expresses disappointment that he can't get the answer to why are we here, Pinky answers that he often finds himself in strange places thanks to The Brain, and the man takes it to mean that our brains often lead us to unexpected places. The people around then begin to worship as a guru and Brain asks them to give them sandal root.
It's hard to keep up with all of Pinky's non sequiturs, but most of them are Beatles references. He ponders "giving peas a chance" and suggests that Brain call him "Mean Mr. Ketchup." Brain dubs him the Mous-arishi instead.
Walter "Concrete" proclaims the Mous-arishi as the leader of the Flower Power generation. We see Frank Sinatra, the Beach Boys and the Smothers Brothers among the people there to hear him speak. The Feebles lay tons of a sandal root in front of him and they begin to sing together: "All you eat is lunch, all you drink is punch, you don't have time to munch, brunch! All you eat is lunch!"
The Brain wants Pinky to keep seeing more followers to collect the sandal root, but Pinky tells him that he can't see anyone else for six months, because he and the Feebles and holding a sing in to teach people to love each other and brush their teeth. The Feebles chime in about how peaceful and quiet it is up here in the mountains and how nice it is to get away from all the screaming girls.
The Brain figures he's ruined as he walks away. He approaches a woman who looks like Yoko Ono waiting at the entrance. She tells him he looks sad and offers to sing him her happy song, which is of course nothing but screeches and yodeling. He leads her up to see them all in the hopes her noise will disrupt them.
The Feebles react:
George: "She's awful!"
Paul: "She's terrible!"
Ringo: "She can't sing!"
John: "I love her!"
Technically, John is called Jim here, and Yoko is "Yoyo Nono," but you get the idea. The Feebles break up and the Mous-arishi is blamed for it. Brain thinks they're okay because they still have the sandal root, but Pinky tells him that Jim and Yoyo took it back to England for Yoyo's latest performance piece.
They sing "All we are saying is take off your pants" because they want everyone to live without pants like the Mous-arishi did. Yoyo covers the sandal root with paint or glue or something before screeching one more time for good measure. Brain plans to mail them back to America so they can once more try to cash in on the nexy big youth fad and take over the world.
The ending song outro is sung in a classic Beatles style ending with the "yeah yeah yeah" from "She Loves You" before Pinky shouts "I've got blisters on my fingers! Narf!" which all but the narf are taken from the end of "Helter Skelter."
It seems like the creative team behind Animaniacs weren't satisfied with just parodying the early Beatles with the previous short and so they added this parody of the later Beatles into the Pinky and Brain show. The problem is that it largely follows the same old thing of making fun of Yoko and blaming them for their breakup. Its just a little too typical, and the constant bits of her screeching wear thin very quickly. I think the other little touches here and there are cute, but considering that Yoko wasn't there in India and the Beatles had quit touring a full year before going there, it just becomes a jumble of the facts and doesn't work as well. I don't really expect them to be accurate here, I just feel like they went for the obvious too often rather than being creative.