Recap
In the apparently normal comic book store, Denise takes a bite from Stuart’s ficus, prompting strange looks from the guys. Denise encourages Stuart to try it, while Bert is already eating another plant. Kripke joins in after Stuart's recommendation. Denise’s pleasure at the taste disappears when she suddenly gags, and Bert explains that she is chewing her cud. Reading from a comic about the human body, Bert mentions that people in this universe have four stomachs because they evolved from cows. Kripke is ready to write off this universe, only to regurgitate his own food and enjoy eating it again.
At a restaurant, Bert uses a modern smartphone to research their new world. Apart from a few minor cultural differences, he says that it closely resembles their universe before the apocalypse. Denise reminds him that people here have four stomachs and are descended from cows. The waiters arrive with four different varieties of grass, which they each enthusiastically eat. Stuart proposes staying in this reality as none of them understands how to save the universe or operate the vari-state quantum entanglement device reliably, and each of their previous destinations turned dangerous. Bert points out that he was happy in the last world, despite the riot that forced them to flee.
When the waiter offers corn for dessert, Kripke orders a large serving for the table. As they discuss what their life could look like here, Stuart imagines that he and Denise could recreate their former lives and suggests that they might even get married. Denise asks whether he is proposing, and Stuart asks whether she is accepting. With both of them repeatedly chewing their cud, Denise admits that she imagined this moment with less vomit in her mouth. Stuart tells her that she does not have to answer immediately, and the waiter arrives with a large bowl of corn.
After having sex in Stuart’s bedroom at the back of the comic book store, Denise tells him that she has considered his suggestion. She agrees they could be happy here: the people are kind, the food is good and the health care is excellent. Bert and Kripke interrupt to announce that they do not want to remain in “Cowtown.” Citing their success in previous universes, including Kripke’s numerous sexual encounters, they ask to take the machine and roll the dice on another reality. Denise is willing to stay permanently, so Stuart gives them the device. Kripke acknowledges that he has not been the best traveling companion but offers no apology. After Bert and Kripke leave, Denise admits that she will miss them.
Kripke places the machine on the store’s counter and assures Bert that, as a renowned physicist, he can operate it. When he activates the machine, however, they appear in a cosmic void and begin falling instead of reaching another reality. Their screaming subsides as they realize there may be no bottom. Neither man can think of a solution, so they resume screaming.
As Stuart and Denise explore the streets of Pasadena while snacking on vegetation, they share an enthusiastic visit to a streetside salt-lick vendor. When they hear a doomsday preacher warning that the universe is collapsing, they recognize him as Raj, who is once again alive in this reality. Raj explains that several distant galaxies and star systems have vanished and, despite his attempts to alert JPL, NASA and the White House, nobody is listening.
Raj believes everything they know and love will disappear within three or four hundred years. Stuart is unconcerned because everyone alive today will be dead by then, but Raj invokes the distant descendants who will be lost. The thought of future generations leads Stuart and Denise to discuss having children in their new home. When Raj insists that nothing can prevent the universe’s destruction, they remain unconcerned, wish him luck and continue on their way. Raj returns to his soapbox to warn passersby that they are all going to die.
Still falling through the void, Bert tells Kripke to press the machine’s button to try to get them out of there. Kripke does so, but the machine doesn't respond. Bert suggests playing Twenty Questions to pass the time, only to give up after asking a single question and frustrating Kripke even more.
When Stuart and Denise return to the comic book store, they find Stuart Prime waiting behind the counter. He demands to know why Stuart gave the machine to Bert and Kripke, then mocks his decision to abandon the mission and spend his life chewing cud. Describing himself as a projection from a collapsing adjacent reality, Stuart Prime explains that Stuart is inextricably bound to resolving the fragmentation of the multistate universe, making him the only person capable of fixing reality. Stuart admits that he does not want the responsibility and, even if he did, he no longer has the machine. Stuart Prime tells him to order another version of the device, holding up the Stuart Fails to Save the Universe comic. Stuart declares himself finished with universe-hopping and storms into the back room. Denise stops Stuart Prime from following him and says, “Let me talk to you.”
In the void, Bert tries to fill the endless time by telling Kripke a rambling story about his childhood geology teacher, the club he inspired Bert to start and the kids who joined. As Bert struggles to remember one boy’s name, an exasperated Kripke wishes that they would finally hit the ground.
After collecting a Japanese food delivery from “ShrubHub”, Stuart joins Denise in the back room for dinner, where she is excited to eat her bonsai tree with soy sauce. Stuart asks whether abandoning the mission is wrong. He argues that he never chose the responsibility and that the catastrophe Raj described will not occur for centuries. As he talks through the consequences, however, he acknowledges that abandoning the mission would cost infinitely many lives across infinitely many realities. Stuart insists that he is not a hero but a failed artist so unsuccessful that he owns a comic book store in every universe they visit.
Denise refuses to make the decision for him but says that anyone can be a hero if they are trying to improve people’s lives. Stuart points out that activating the machine could take them somewhere much worse. Denise reassures him, “There are no bad situations as long as I’m with you.” They kiss despite both chewing their cud.
Later, a UPS driver delivers a large package to the store. Stuart and Denise know him as Gary, but he does not recognize them. They explain that they know him from alternate realities: one version was married to Denise, although the marriage did not work out, while another was dead. An incredulous Gary leaves, muttering that he hates his job.
Inside the package, Stuart and Denise find another vari-state quantum entanglement device, complete with instructions and a warranty. The manual describes it as a quantum echo that simultaneously exists and does not exist. When activated, it will merge with the original machine. Before activating it, Stuart tells regular customers Kyle and Trevor that he and Denise are traveling to another universe to prevent reality’s destruction. Trevor is more interested in getting a discount on a water-damaged comic. After Stuart refuses to budge on the price and activates the device, he and Denise disappear. Kyle tells Trevor that he can probably just take the comic now.
After Stuart and Denise materialize beside Bert and Kripke in the endless void, the quantum echo merges with the original machine as the device leaps from Kripke to Stuart. Kripke explains that they appear to be trapped between universes, colorfully describing it as an “interdimensional taint”: “Think of it like being stuck between the balls of one universe and the asshole of another,” he adds, prompting Denise to call him disgusting. When Denise urges Stuart to save them, Bert says that they tried, but the machine did not work. When Stuart explains that the machine failed because neither Bert nor Kripke was chosen to save the universe, Kripke sarcastically asks whether Stuart was. Denise supports Stuart’s claim but objects when he compares himself to Neo, or possibly Jesus. Stuart presses the button, and the four travelers escape the endless void together.
They arrive in an ordinary-looking version of the comic book store. Stuart thinks that everything appears normal, only for Denise to reply without speaking. As the group realizes that they can hear one another’s thoughts, Kripke immediately worries that this will be a problem for him. He then involuntarily reveals that his mother bathed him until he was twelve.
