Vari-State Quantum Interference Device
The Vari-state Quantum Interference Device is the machine at the center of the multiverse catastrophe. Built at Caltech by Leonard Hofstadter, Sheldon Cooper and Howard Wolowitz, the device was damaged when Stuart Bloom accidentally knocked it off a table, triggering the collapse of his original reality into a post-apocalyptic nightmare.
When an alternate Stuart from another reality, known as Stuart Prime, first describes the machine, he calls it “some kind of quantum entanglement thing”, while Raj later identifies it as a Vari-state Quantum Interference Device. The terminology is not entirely consistent: a comic book narrated by Stuart Prime calls it a Vari-state Quantum Entanglement Device, while an advertisement in the same comic refers to it as a Vari-State Quantum Device.
The device seemingly opens passages between different realities. When activated, it forms an interdimensional bubble around people nearby and transports them elsewhere, usually taking the machine with them. Anyone outside the bubble can be left behind, as happens to Denise in the post-apocalyptic reality. The device can also create more than one bubble: when the group escapes the AI-controlled universe, they are divided into two pairs and taken to separate destinations.
Stuart and his companions initially struggle to operate the device and cannot reliably control where it takes them. After studying the replacement device’s manual, Stuart concludes that moving laterally between realities will not restore the universe: they need to travel through time. He believes the unfinished machine needs a “steering wheel” capable of returning them to the time and place before the catastrophe.
The device’s operation is also affected by the rules of the reality in which it is used. In the magic world, which does not follow the conventional laws of physics, the machine requires magic to function. One of its trays houses a crystal component; when that crystal burns out in the tropical reality, Stuart restores the device by replacing it with red quartz.
Although other people can activate the device, successfully traveling between realities appears to require Stuart’s presence. When Bert and Kripke use it without him, they wind up trapped in a void between universes and are unable to make the machine work again. Once Stuart joins them and regains the original device, he activates it and continues their journey. Stuart attributes this to being the person “chosen” to save the universe, while Stuart Prime explains that Stuart’s quantum entanglement with the original incident makes him uniquely connected to resolving the collapse of the multiverse.
When the group encounters lab-coated versions of themselves with another quantum device, Kripke uses their own machine to follow the other team’s “slipstream” through several previously visited realities. A third group wearing army uniforms, which initially appears to be another alternate team, seizes the lab-coated group's device.
By retracing their route through previous realities, Stuart and his companions return to the earlier encounter and become the army group that seizes the improved device from their lab-coated doubles. They return to the war zone carrying both machines before using the improved device to leave. Their next destination finds them trapped inside a comic book.
101 “Spoiler: Gary Dies”
In the post-apocalyptic reality of 101 “Spoiler: Gary Dies”, an alternate version of Stuart appears at the Comic Center of Pasadena and tells Stuart that the catastrophe can be undone if he reaches the machine at Caltech. Before he can explain fully, Stuart Prime is pulled back through a wormhole.
At Caltech, Stuart, Bert and Denise encounter Raj, who has spent years imprisoned, studying what went wrong. Raj confirms that Leonard, Sheldon and Howard built the device and believes he can use it to restore reality. After the group reaches the guarded machine, Raj is shot by Kripke before he can use it. Stuart and Denise try to follow Raj’s notes, but the device activates before they can read the final instruction. The machine creates an interdimensional bubble that pulls Stuart, Bert and Kripke into another reality, leaving Denise behind in the post-apocalyptic world.
102 “Spoiler: Zack’s in This One”
In 102 “Spoiler: Zack’s in This One”, Stuart, Bert and Kripke arrive with the device in an apparently peaceful Pasadena that is actually controlled by an AI overlord. Kripke concludes that Denise must have been too far from the interdimensional bubble to travel with them.
Because none of them truly understands the machine, Bert and Kripke try to find Sheldon and Leonard at Caltech, hoping they can explain how to use it. Denise later finds the device at the comic book store and contacts the Resistance, believing it may help defeat the AI overlord.
When Stuart admits the device cannot save this reality and can only help them escape to another one, the Resistance turns on the group. During the chaos of a drone attack on the Resistance headquarters, Kripke tries to flee with the machine, but Stuart, Denise and Bert catch up just as it activates. This time, the device creates two interdimensional bubbles, separating them into two pairs: Stuart and Denise, and Bert and Kripke.
103 “Spoiler: Bert is Magic”
In 103 “Spoiler: Bert is Magic”, Stuart and Denise arrive with the device in a reality where magic is real. When Kripke later tries to activate the machine, it doesn’t work, leading him to conclude that a universe unconstrained by the laws of physics may require magic to make the device work.
Stuart and Kripke seek help from Bernadette Rostenkowski, a master sorceress who has been stripped of her powers. After tricking Stuart into helping restore her magic, Bernadette transforms into a five-story-high demon and tries to capture the device so she can rule every world.
As Bernadette attacks the comic book store, Stuart urges Bert, who is a powerful wizard in this reality, to get the machine working. Bert does not know the correct spell, but his simple commands are enough to activate it. The device transports Stuart, Denise, Bert and Kripke to another reality, with Kripke still in penguin form until they leave the magic universe.
104 “Spoiler: Stuart Makes a Wallet”
In 104 “Spoiler: Stuart Makes a Wallet”, Stuart appears to have been separated from the device and institutionalized in a reality where he is made to see the other universes he experienced as delusions. After he is released into a seemingly perfect suburban life with Denise and their children, Stuart finds a Stuart Fails to Save the Universe comic book apparently planted by Stuart Prime at the Comic Center of Pasadena.
The comic retells the device’s origin, showing Leonard, Sheldon and Howard building a vari-state quantum entanglement device before Stuart accidentally damages it. It also warns Stuart that he must escape the “prison” he is trapped in. An advertisement in the comic leads him to order a “Vari-State Quantum Device” from the Inter-Dimensional Novelty Company of Southfield, Michigan.
Tired of your current universe? Travel between realities. Impress your friends. Scare the girls. With the Vari-State Quantum Device, you can now take the trip of a lifetime to a nearby alternate reality. Explore your existence in another universe. Will you be a titan of industry? A jet-setting playboy? An elite athlete? There’s only one way to find out.
When Stuart activates the device at home, he and Denise appear to awaken in pods alongside Bert and Kripke. Stuart recognizes this Matrix-like scene as another layer of the deception and tears through the illusion, revealing the device inside a vast white space. He warns the group that there is no way to know where they will end up next, but activates it anyway.
105 “Spoiler: Bert Gets Married”
In 105 “Spoiler: Bert Gets Married”, the group arrives with the device in a tropical paradise. Shortly after some welcoming locals invite them to stay in their village, Stuart hears the device making a crackling sound. He opens a tray and discovers a burned-out crystal emitting smoke, leaving the group without a reliable means of escape.
The following morning, Stuart admits to Denise that he has been unable to repair the device, joking that he comes from a long line of people who call someone else to fix things. He hopes that whoever has been sending him messages will provide instructions. When Stuart and Denise encounter a local woman searching through bear droppings for signs and omens, he realizes that a message in this reality might be delivered in the same way.
Stuart searches through the bear droppings and eventually uncovers the instruction “Use red quartz”. Neither he nor Denise knows where to find any, so they consult geologist Bert, who identifies a piece in Gavel’s necklace. After Kripke’s lessons about personal ownership spread through the village, Gavel refuses to hand it over. Stuart attempts to steal the necklace that night, but Gavel catches him and takes it back.
During Bert and Chana’s wedding, the villagers’ arguments over monogamy and private property erupt into a brawl. When Gavel’s necklace is torn off in the fighting, Stuart manages to retrieve it and places the red quartz inside the device. The machine powers up successfully, allowing Stuart to activate it and transport the group away from what was once paradise.
The group arrives inside the comic book store with the device in a seemingly ordinary Pasadena. They wonder whether they have finally reached a normal universe. Denise leans towards a green plant on the counter and eats one of its leaves before agreeing that it seems normal.
106 “Spoiler: Corn is Delicious”
In 106 “Spoiler: Corn is Delicious”, the group arrives with the device in a reality where humans evolved from cows. Its technologically advanced society closely resembles their world before the apocalypse, aside from its inhabitants being ruminants. Because the previous universes have all proved dangerous and they still do not know how to work the device, Stuart and Denise decide to stay in this reality.
When Bert and Kripke choose to try their luck in another world, Stuart allows them to take the quantum device. After Kripke activates the machine, an interdimensional bubble forms around him and Bert, but instead of transporting them to another reality, it leaves them falling through a cosmic void. With no bottom in sight, they conclude that they may keep falling forever.
Bert later urges Kripke to activate the device again. The machine creaks and beeps but fails to transport them out of the void. Meanwhile, Stuart Prime confronts Stuart over giving the device away and abandoning his mission. He explains that Stuart is inextricably connected to the resolution of the fragmented multiverse because of his quantum entanglement with the original incident. Stuart Prime puts it more simply: Stuart is the only person who can save the universe.
When Stuart points out that he no longer has the machine, Stuart Prime gives him another copy of Stuart Fails to Save the Universe and suggests ordering a replacement. Stuart questions how another device can exist, but Stuart Prime points to the absurdity of their conversation as evidence that ordinary logic no longer applies.
A replacement “interdimensional transport device” is subsequently delivered to the comic book store. The package includes instructions and a warranty, and Stuart discovers that the machine also has Bluetooth. When Denise asks how another device can exist if Bert and Kripke took the original, Stuart consults the manual. After reading warnings including “Don’t use near water” and “Caution. Small parts, choking hazard”, he finds the explanation: “This is a quantum echo of the original device. It both exists and does not exist. And when activated, it will merge with the original device.” Denise decides to stop asking questions.
Stuart activates the quantum echo, transporting himself and Denise into the void with Bert and Kripke, where it merges with the original machine. Stuart says that the device failed for Bert and Kripke because they were not chosen to save the universe as he was. He then activates the original device and transports the four travellers into another seemingly ordinary version of the Comic Center of Pasadena, where they discover that people can hear one another’s thoughts.
107 “Spoiler: Dexys Midnight Runners Get a Royalty Payment”
In the telepathic reality of 107 “Spoiler: Dexys Midnight Runners Get a Royalty Payment”, Stuart has been studying the instruction manual that came with the replacement quantum device, believing it to be another message from whoever has been guiding him. He has learnt that they cannot restore the prime universe to its original state because they are moving laterally between realities rather than along a fourth-dimensional axis: time.
Stuart explains that Sheldon and Leonard never completed the device. He believes it needs a “steering wheel”, a control mechanism capable of taking them back to the time and place before everything went wrong. Kripke suggests adapting a satellite controller using components from Caltech’s engineering department.
When the group reaches the engineering lab, they discover four lab-coated versions of themselves with another quantum device. Lab Coat Kripke activates their machine to escape, prompting Kripke to activate his own group’s device in an attempt to catch their “slipstream”. A chase through several previously visited realities ends when the two groups collide in the reality where humans evolved from cows.
The two Stuarts discover that each was told he alone could save the universe. As the groups question why they were sent on the same mission, a third team dressed in army uniforms arrives with its own quantum device. Army Kripke seizes the lab-coated group’s machine, leaving the soldiers with two devices and the lab-coated group stranded in the cow universe.
After Stuart and his companions use their device to follow the soldiers into a war-torn reality, they quickly activate it again to escape. They arrive in another version of the comic book store, where they discover that they have horses’ bodies below the waist.
108 “Spoiler: We're as Confused as You Are”
In the centaur reality of 108 “Spoiler: We're as Confused as You Are”, Stuart decides that the group must return to the war zone to obtain the quantum device fitted with a controller from their army-uniformed counterparts. Denise reminds him that they nearly died there, prompting Stuart to suggest “scooching it”. When Bert asks whether there is a “scooch button”, Stuart replies, “Maybe,” before adjusting a knob and activating the machine.
Back in the war-torn reality, now wearing army fatigues, the group is ordered to join Charlie Company. Once they reach the trenches and his companions urge him to get them out of danger, Stuart admits that he left the device in the barracks for safekeeping. The following morning, they are caught trying to abandon their unit and are imprisoned.
In their cell, Stuart has a revelation: they do not need to find the other machine in the war zone. Instead, they can retrace their journey through the centaur and telepathic realities to the cow universe, where their lab-coated doubles last had the improved device. Bert describes the plan as “trippy”, while Kripke points out the inconvenient fact that they are in prison.
At their court-martial, prosecutor Penny presents the confiscated quantum device as equipment for relaying information to the enemy. After the group is sentenced to death by firing squad, she offers to commute their sentences to a life of hard labor if Stuart uses it to transmit false battle plans. Stuart eagerly agrees and pretends to prepare the transmission, loudly counting down as Denise, Bert and Kripke edge closer. He activates the machine, transporting the four of them and Penny back to the centaur reality.
At Denise’s urging, Stuart uses the device again to return to the cow universe, leaving Penny behind. Still wearing their army uniforms, the group encounters their earlier selves and the lab-coated doubles, revealing them to be the soldiers they previously followed. On Stuart’s orders, Kripke takes the improved device from his lab-coated counterpart. The group returns to the war zone with both devices.
In the war zone, the group waits for their earlier selves to arrive, allowing the pursuit that led them to the centaur reality to take place. Once they appear, Kripke activates the newly acquired device and the group disappears.
In another version of the comic book store, Stuart and his companions are trapped inside a comic titled Stuart Fails to Save the Universe TRAPPED!, their cartoon likenesses speaking on its cover. A mysterious entity known as the Adversary instructs Kyle and Trevor to keep them there by refusing to sell the comic.
109 “Spoiler: We Couldn’t Get Green Lantern”
After using the improved quantum device to escape the war-torn reality for a third time, Stuart and his companions begin 109 “Spoiler: We Couldn’t Get Green Lantern” trapped inside a comic book. Separated from the machine, Stuart turns to his comic book knowledge to try to find a way out.
Following Bert off the cover and onto the splash page, the group return to their three-dimensional forms on a city street. Stuart quickly identifies their surroundings as Gotham City and proposes finding the Cosmic Treadmill, which Denise immediately recognizes as a means for the Flash to travel between universes.
The group travel to Central City and eventually enlist the help of Jay Garrick, the Golden Age Flash. In his garage, Jay explains that they should grab the treadmill’s handles once he reaches sufficient speed. His instructions leave them doubtful, but the return of Mr. Freeze gives them little time to question the plan.
Clinging to the handles, Stuart and his companions travel with the Flash through the cosmos, passing orbs containing different realities before arriving back in the comic book store. Though the Stuart Fails to Save the Universe TRAPPED! comic remains on display, they are now free from its pages.
Although the treadmill has helped them escape the comic book, they are back in the store where the Adversary ordered Kyle and Trevor to keep them imprisoned. Kyle warns that the Adversary will be angry to find them there in person and will look for someone to blame.
When Kripke tries to leave the store, he nearly steps into an endless black void beyond the entrance. As Stuart looks down at the dark expanse, he observes, “This is not Pasadena.” Unexplained audience laughter prompts Kripke to ask, “What the hell was that?”
This page has been updated up to episode 109 Spoiler: We Couldn't Get Green Lantern