The crew is chilling out in the Planet Express living room when the Professor enters. He says that he thinks they work too hard, and he thought it might be nice to do something in a social setting and finally get to know each other. He recommends Oktoberfest in three months and the rest of the crew cheers happily.
Three months later they attend Oktoberfest in Germany. As Fry is from the 20th Century he is ready to party and drink some beer. But apparently Oktoberfest has now changed into a sophisticated exhibition of German food, drink, culture and a classy celebration of how humans have evolved. Leela tells Fry to be on his best behavior, but Fry still wants to drink - unfortunately he cannot even get Bender to join him. Bender walks away and passes by a Sausage Kompetition sign, deciding to join it. He then meets Elzar who tells him that he cannot paticipate in the competition with ordinary meat, stating that exotic meat is needed to stake a top placing in the competition. In the main tent, Fry is still trying to get more beer but it is hard for him to do so as it is a sophisticated event with the beer cups being kiddie sized. He then asks where all the beer comes from, with Hermes pointing that it comes from the large Oktober Brau barrel, which unfortunately for him it is guarded. He then finds another way by drinking beer from a large jar the other guests have spit out their beer in. Soon after he is drunk and dances on the table, surprising the other guests (even causing the Countess who was observing him to faint) and the rest of the crew say they are embarrassed of him, but Fry does not care, and even offers Leela to join him in getting drunk and doing the chicken dance on the able. Leela refuses and then exclaims that Fry's a neanderthal and an embarrassment, and decides to break up with him.
Fry is then seen sad and came across a disappointed Bender, who is upset because he cannot participate in the Sausage Kompetetion. They then stumble across a booth explaining the origins of Oktoberfest, which apparently begins at Neander Valley by Neanderthals. Bender also finds out that there were mammoths who were frozen in the ice for around 30,000 years, and decides to go to Neander Valley with Fry to look for some mammoths which he intends to make sausages from. Bender manages to retrieve a mammoth from the ice and uses a mulcher to make sausages out of the mammoth, with Fry helping to push the mammoth into the mulcher. But suddenly Fry's hair got stuck into the mulcher and is pulled inside it. Fry cries for help but Bender does not notice him and continues making the mammoth sausages.
Back at Oktoberfest, a judge samples the mammoth sausages that Bener has made and finds it great, qualifying him for the next round. Leela then shows up with the rest of the crew and compliments Bender. Leela then asks if she could sample some of the sausages, with Bender giving her a mammoth hot dog to try for herself. As she is eating the hotdog, a speck of Fry's hair appears from her mouth, with Amy exclaming that the hair coming out from her mouth looks like Fry's. Leela dismisses this as a cruel joke, when she suddenly sees the sausage she was eating includes some of Fry's hair and bits of his clothing, making her scream in horror.
Back at the Planet Express building the crew gathers around a coffin where the sausage now lies. Leela becomes stricken with grief and begins crying. Later that day, she visits a forgettery salon where she asks her memories of Fry to be removed, which then shows the nerves inside her brains being cut off. The next day, Leela comes to work acting cheerful as the other members feeling gloomy, with Leela asking who had died. They then resume their work as usual, with Leela claming that they need to get a new delivery boy. Hermes then says that they need to accept that Fry's gone and that they need to move on with their lives.
Fry is then shown regaining consciousness frozen in a sheet of ice, trying to recall what had happened to him. A flashback is played to a week earlier where Bender was making the mammoth sausages with Fry. It was revealed that Fry managed to free himself from the mulcher, but not before it shreds his jacket, pants, shirt & underwear and a piece of his hair. After pulling himself out, he then lands barely inches away from the hole they had dug up to retreive the mammoth, with Fry breathing a sigh of relief. But suddenly the ice beneath Fry breaks, causing him to fall into the hole.
As Fry lands in the hole he tries to get up, but is then knocked out by a cave rock. Fry then realizes he is trapped in the ice and calls for help. He then sees two shadows heading his way, who then raise their hammers and break Fry free from the ice. He then thanks those who released him, but gets surprised as he sees the missing Neanderthal world underneath the icy layer above. The Neanderthal male who released him asks how he got trapped in the ice, with Fry stating that he knocked his head hard. As he removes the chicken hat he was wearing it shows a large lump on his forehead, with the Neanderthal male claming it looks normal. Fry then asks who he is, with the Neanderthal female who rescued him saying that he is probably a Neanderthal too.
Back at Planet Express, Leela, Bender, Hermes and Amy gets ready to deliver some goods to McPluto. Leela then asks what they are delivering, with Hermes stating that they are delivering hamburgers and French fries, trying to avoid mentioning the word 'fries'. He also then informs that they asks for the shipments every Saturday, actually covering up the fact that the shipments are wanted every Friday. Leela then spots the chicken hat Fry wanted to give her, stating that it is cute, but it makes her feel sad. Bender, Amy and Hermes, fearing that Leela might turn violent escapes through the spaceship's escape pod.
Fry is then shown staring at a wild boar's tail, which resembles Leela's ponytail. The Neanderthal male asks why Fry is staring at the wild boar's butt, with him stating that it makes him feel happy and confused, but also sad and wistful. The Neanderthal female then states that the Neanderthals have always beeen sad and it is in their nature. Fry then asks why this is so, with the Neanderthal male explaining that 30,000 years ago in virtual Neander Valley, life for them was peaceful. When the Homosapiens arrived, the Neanderthals suggested that they should interbreed, creating one happy species. But the Homosapiens treated them like second-class commodities, driving them out from the valley and forcing them into an isolated crevice. Shortly thereafter, the sky above them became frozen, and that is why they are trapped underneath. Fry then realizes that his feelings of being called primitive and people refusing to mate with him are well placed.
At the Planet Express building, Scruffy retrieves a note attached to a raven and passes it to Bender. Bender than says that his mammoth sausages has made it to the finals of the competition and that they need to go back to Oktoberfest for the closing ceremony. Leela than looks at the chicken hat while wondering about Oktoberfest, causing the others to stare at her in fear. But then Leela says that it would be fun to go.
As Fry is seen scratching himself, a Neanderthal boy runs past to him to the Neanderthal Chief, stating that he has found a hole in the ice above that leads to the outside. Fry suggests that since they aren't trapped anymore they can finally take back the outside world from the Homosapiens, rallying his fellow Neanderthals to do so. Leela is then shown staring at a pumpkin whose color closely resembles Fry's hair color. Amy than asks Leela why she is staring at the pumpkin, with Leela stating that it's something about the pumpkin's color which make her feel sad and confused. Leela then says she should feel happy, since Bender's sausage won 3rd place. Bender, however was not satisfied with his award. Zapp (as a sausage judge) and his assistant Kif appear on the table Leela is sitting at, trying to woo her as he always does. Suddenly, the ground beneath them starts to shake, causing them to run out from the tent to see the mountain in front of them crumble, revealing an army of Neanderthals on mammoths (with Fry on top of one of them), charging towards the Oktoberfest site.
As the Neanderthals charge into the Oktoberfest site, Fry orders them to smash things. The crew then runs away, with Bender managing to get a few glasses of beer as the Professor slowly passes by. A mammoth is seen ramming through the arts tent, sticking a few paintings on its horn as a Neanderthal is shown smashing puppets from a clockwork. Bender then comes across the 2nd place sausage competition winner, putting him into a rhino's path and claming his 2nd prize sash and trophy. Fry then orders for the giant sloth to be released, with Leela and the others running away as Hermes stands still screaming in fright. As they try escape, a Neanderthal tries to attack them, but Leela easily dispatches him. Zapp then tells Leela not to fear and calls for his fleet of unmanned drones (with pilots in them actually). A mammoth is seen charging towards Zapp, causing him to drop the controller of the drones with the mammoth stepping on it, causing the drones to crash and explode on the ground. Hermes is then shown taking his time screaming as the sloth tries to attack him. Bender then notices the 1st prize winner of the sausage competition hiding beneath a table. Bender heads towards him and offers to protect him, carrying him on his back while giggling in an evil manner. A fleet of tanks is then shown shooting electric beams towards the mammoths, which only causes their fur to rise up. The mammoths head towards the large Oktoberfest Brau barrel, sucking out the beer inside it and spraying it towards the tanks, causing them to explode.
The Nimbus is then shown hovering over Fry, causing him to order the Neanderthals to prepare the catapult. Zapp is then seen inside, gloating about the technology that the Neanderthals do not possess. He then notices the catapult beneath him, which then fires a sabertooth tiger through the glass to attac Zapp. The Nimbus then crashes onto the ground, but out of the smoke the Planet Express spaceship appears, fighting back with Leela piloting it. Leela heads towards the mammoth Fry is riding, as it takes the spaceship head on and slams it onto the ground. The two then duel it out on top of the Planet Express ship, with Fry stating that his people deserve the equality that they are entitled to have. Fry manages to knock off Leela's chicken hat, with Leela knocking off Fry's skull helmet in turn. As Leela is about to jab Fry's spear into him, she notices the orange color of Fry's hair while at the same time Fry notices the purple color of Leela's hair. After asking each other if they had met before, the two share a passionite kiss. The Neanderthal female wonders what Fry is doing with the homosapien woman, with the Neanderthal male stating that they're interbreeding. The rest of the Neanderthals then decide to stop fighting and make love with the other Homosapiens. The Neanderthal Chief then sees the change made by Fry and Leela's kiss, and decides to seek peace with the homosapiens instead of war. Zapp agrees and decides to call the fight a draw, with the people around them cheering. Hermes is then seen being cuddled by the sloth. As Leela continues kissing Fry, she regains her memories of him, with the nerves in her brain joining back together. The lump on Fry's head then shrinks, and he remembers who Leela is as well. Bender then appears, showing off the 1st prize award he got from the original winner, whom he disposed of by throwing into a glacier.
Back at the main tent the Neanderthals are seeing celebrating with the Homosapiens, dancing and drinking away. Bender is then shown serving a large mammoth rib steak to Zapp and the Neanderthal Chief, placing in on the table and causing it to tip over. Fry then states that this is the Oktoberfest he knew from his day, with Leela admitting that this version is more fun than the original. Leela then notices that the Chicken Dance song is playing and gets onto the table, offering Fry to join along. Fry declines and says that he'll let her embarrass him for once, as Leela proceeds to do the Chicken Dance.