- "Detecting trace amounts of mental activity. Possibly a dead weasel or a cartoon viewer."
- ―Big Brain
Fry is preparing for a mission, only to learn that Bender and Leela have just returned. Not only finishing the mission, but doing it even better than usual since they earned medals for the mission while he was looking up curse words in the dictionary.
While Leela is on a date with Chaz, the mayor's aide, she asks Fry to walk Nibbler for her. Fry feels that he is useless, only to have Nibbler, supposedly a simple animal, tell him otherwise. Nibbler then knocks Fry out, drags him to his small spaceship, and takes him to planet Eternium. After being introduced to the Nibblonians, Fry's told his importance: he has a unique genetic disorder which resulted in him lacking the delta brainwave, due to him becoming his own grandfather. This rendered him immune to the attack of the Brainspawn a few months ago, an attack which no-one else on Earth remembers.
The Nibblonians reveal the Brainspawn's plan: to collect all knowledge in the universe and destroy the universe so no new information pops up. Fry, because of his immunity, is the only person who can stop them.
In other words, Fry is the most important being in the universe. The Nibblonians have made a quantum interface bomb, which will send the Infosphere into an alternate dimension forever. Fry's mission is to smuggle it into the Infosphere and detonate it.
The Nibblonians bring Fry to the Infosphere just as it collects the last of all the data in the universe. It opens to scan itself, the final piece of information. This is the only chance to get in, so the Nibblonians send Fry in on Scooty-Puff, Jr., a cute little space vehicle. Fry arrives at the center of the sphere, rendered invisible by his genetic abnormality as long as he avoids intense thinking. He is about to activate the bomb, but realizes that while he is there, he can find the answers to any question in the universe.
He asks questions: "What's stamp glue made of?" (toad mucus) and "What killed the Dinosaurs?" (the Infosphere himself killed the dinosaurs). Fry is discovered and the Brainspawn try to stop him, but his immunity protects him. He tries to escape, but the poorly made Scooty Puff Jr. falls apart, trapping him. The Brainspawn identify Fry as "The Fabled One" and gloat that he cannot escape. Their laughing ceases when Fry holds up the bomb and activates it. The Brainspawn remind that him that he is doomed to enter the alternate universe with them. One brain adds that they'll also form a clique that Fry won't be part of. But Fry boasts that he is glad that his life had a purpose: "Leading good to victory over evil." The Brainspawn question his motivations, suggesting that the Nibblonians are not as good as they appear. They suggest that Fry inquire about the night of December 31st, 1999, the date Fry got frozen. Nibbler nervously tells Fry not to ask, saying that it would be boring, so he concedes, only to be urged by the Big Brain. It is revealed that Nibbler unbalanced the chair that Fry was sitting on that night, tipping him into the cryogenic tube and bringing him to the future. Nibbler explains that Fry was the only person who could carry out the mission against the Brainspawn's Infosphere. As Fry grapples with the shock that the Nibblonians ruined his life, he and the Infosphere are sent to the alternate universe.
Meanwhile, Leela is on a date with Chaz, having a luxurious dinner at Elzar's Fine Cuisine. Chaz reserves the rocket ice rink specially for Leela, denying its use to the orphans from the Cookieville Minimum-Security Orphanarium who were supposed to visit the rink. Leela, having grown up as an orphan herself, tries to persuade Chaz to allow the orphans to use the ice rink, but he refuses. Leela realizes that Chaz abuses his position and completely ignores the needy. She shoves his badge in his mouth and leaves.
In the other dimension, the Brainspawn decide to spend their eternity singing American Pie. Fry, on the other hand, wishes that the Nibblonians hadn't frozen him. The Infosphere informs him that it is possible for him to go back in time to stop Nibbler, explaining that there is a nexus point between dimensions at the space-time that he entered the cryogenic tube and only Fry can return there. The Big Brain endorses this, as it would be a win-win situation - Fry can have his old life back and the Brainspawn can understand and destroy the universe a millennia later. Fry accepts their offer. The Brainspawn then begin calculating to send Fry back. Fry asks the Brainspawn if they check their calculations. The Big Brain says "Our calculations are always correct, for we are gigantic brains." and Fry is transported to the cryogenics lab.
On December 31st, 1999, Nibbler places a prank order for I.C. Weiner, but future Fry appears behind Nibbler under the desk, just before his past self is frozen. He restrains Nibbler, who is confused at this paradox. Fry assumes that Nibbler has traveled through time as well, but Nibbler explains that his people lack that ability, but do live long, and Fry first met Nibbler when he was a thousand years older. However, Fry refuses to let himself be frozen. Nibbler pleads that the Nibblonian sages have foreseen that in a thousand years, the universe will depend on Fry. Because he would have died of old age almost a thousand years before the mission was to take place, they had to freeze him in 1999. Fry points out that they could've asked him: Nibbler says that they were afraid that he would refuse. Fry denies it, saying he loves the future. The Nibblonian then asks why Fry is choking him right now: Fry asserts that he doesn't "like being used" and puts Nibbler down. Leaving the choice to Fry, Nibbler asks if there is anything he wants to save in the future and Fry realizes the only thing worth saving is Leela. Fry mentions this to Nibbler, who mysteriously notes that Leela may be the "Other" and advises Fry not to give up on her. He promises if Fry makes the right choice, back in the 31st Century Nibbler will help Fry win Leela's heart. As New York counts down to New Year's, Fry gives in and unbalances the chair himself, freezing his past self. Before he fades away, he yells "Just remember that Scooty Puff Jr. suuuucks...!" Nibbler vows that in a thousand years, he'll "get right on it".
Back in the 31st century, Fry escapes the InfoSphere on a much more capable Scooty-Puff, Sr. (The Doom-Bringer) and Nibbler returns Fry to Earth, blanking Fry's mind of what happened to remain undercover, but not before handing Fry a flower. At Planet Express, Fry gives Leela the flower. Leela, touched, gives Fry a kiss, much to Fry's excitement.
- Fry, Amy, and Zoidberg pretend that they constitute a delivery team and rehearse a delivery.
- Fry uses a quantum interface bomb to blast the brains (and himself) into an alternate universe. Later, after some time-travel, he blasts the brains (only) into an alternate universe.
- The giant brain uses some sort of telepathic energy to serve as a hand for typing on a computer keyboard.
- Fry (because he time-travels to December 31, 1999) exists briefly in two forms - his 20th century self and his 30th century self.
Fry and Leela
Fry, attempting to assuage his own guilt over missing a delivery mission, wants to make it up to Leela by taking her out to dinner. Typical of Leela, she rejects Fry. In fact, not only does she reject him categorically, she also explains that she is going out with Chaz, the mayor's aide.
When Fry and Leela cross paths while she is out on her date with Chaz, Fry has a brief moment of happiness due to his hope that the date is not going well. Leela crushes his hopes when she tells him that the date is going very well, asking him to walk Nibbler.
While Fry from the future argues with Nibbler of 1999, Fry mentions that he has feelings for Leela, but also that she doesn't care for him. Nibbler offers to help Fry with respect to Leela, if Fry will agree to push his 1999 self into the cryo-tube. Fry is won over to Nibbler's request when Nibbler frames the issue as "save yourself or save Leela."
On returning to the office from her bad date with Chaz, Leela has Bender burn Chaz' face out of a photo of Leela and Chaz together. While Leela looks at the photo with a hole in it, Fry walks into the room and appears, from Leela's perspective, in the hole where Chaz' face had been. Leela is happy to see Fry and actually gives him a kiss on the lips.
- Elzar bams a cockroach to death with a loaf of bread.
- Fry savagely kicks a robotic trash can, a mother of six kids, knocking her over on her side.
- Nibbler knocks Fry unconscious with a sock-weapon.
- At the Feast of A Thousand Beasts, an indefinite number of beasts are eaten alive.
- The brain console depicts a toad being harvested for its mucus.
- The brain console depicts a giant brain killing dinosaurs.
- Leela stuffs Chaz' wallet into his mouth.
- 30th century Fry chokes 20th century Nibbler.
For the second time, Nibbler reveals that he can talk, this time to Fry. In "The Day the Earth Stood Stupid", Nibbler revealed his identity to Leela, but she fell victim to the worldwide memory lapse, so Fry is temporarily the only earthling who knows Nibbler's identity.
The brain console reveals that it wasn't accidental that Fry fell into the cryogenic chamber back in 1999: Nibbler was there and he blew on Fry's chair to make sure Fry would fall into the chamber. It is also revealed that Nibbler himself placed the phone call to Panucci's Pizza to be delivered to I.C. Wiener at the cryogenics lab.
After returning to Earth, Fry tells Nibbler, "If you ever need a savior again, just ask." Nibbler provides some foreshadowing with, "We will. We will." Not long afterward, Nibbler erases Fry's memory, so once again, no one on Earth knows that Nibbler can talk.
Also according to Nibbler in this episode it is likely Fry is his adoptive father-in-law in this episode and thus becoming Fry's pet himself and Nibbler might have been his pet for real. He also gave his adoptive father-in-law a flower as a surprise for Leela.
Fry discovers that he is the single most important person in the universe due to his lack of a delta brain wave. In The Day the Earth Stood Stupid, he saved Earth, but here he saves the entire universe. His unique importance and in particular the unique importance of his brain disorder, is revisited in "Into the Wild Green Yonder".
In addition to explaining Fry's importance, Ken the Nibblonian also explains that Fry's delta-brain-wave disorder is a result of "certain actions" performed by Fry, in "Roswell That Ends Well", which resulted in Fry being his own grandfather.
After Fry transports himself and the brains to an alternate universe, the brains send him back in time, to the night in 1999 when Fry was frozen. Nibbler is there at the cryogenics lab, hiding under a desk, when future-Fry arrives. Future-Fry grabs Nibbler and has a brief conversation in which he learns that Nibbler's people are long-lived and incapable of time-travel. So Nibbler was at the cryogenics lab normally, without the use of time-travel. This explains the scene in "Jurassic Bark" where we see Nibbler hiding in the wastepaper basket at the cryogenics lab.
Just before future-Fry ceases to exist, he asks Nibbler to remember that Scooty-Puff Juniors (the toy on which future-Fry hoped to escape from the Brain Sphere) suck, so the next Fry (the one now in the cryo-tube) will have a means of escape when the time comes.