- This page is for Kentucky Kaiju, the episode. For the character of the same name, see Kentucky Kaiju.
Fred takes the gang to the newest Kentucky Kaiju movie at the San Fransokyo movie theater. Suddenly, Go Go Tomago receives a news report that Globby is breaking into the San Fransokyo bank. Big Hero 6 springs into action and confronts Globby at the vault. Having expected the team to arrive, Globby quickly separates Hiro from the rest of the team until Wasabi prepares to attack Globby along with Baymax and Fred, prompting Globby to retreat, but not before he taunts Hiro for lacking powers and relying on his friends to protect him. Somewhere else, Obake is monitoring the team when Globby enters. Globby asks why Obake instructed him to only fight the heroes, to which Obake reveals he wants to plant doubt in Hiro and observe what Hiro does with that.
Meanwhile, Hiro is left in dismay over feeling useless. Hiro decides to get to work on a new invention: the Nano-Dex, a nano-technological shirt that enhances the wearer's muscle fibers to grant superhuman strength. At the pier, Fred, accompanied by Heathcliff, is waiting for the Kentucky Kaiju animatronic Fred ordered. The package arrives in a freighter Fred searches through the styrofoam to find the animatronic, which turns out to be a miniature toy. Disappointed that the animatronic is not life-sized, Fred comes up with a new plan for acquiring an authentic Kentucky Kaiju.
After Hiro puts the Nano-Dex on, he and Baymax are called by the team to battle Noodle Burger Boy. Hiro takes the robot head-on with his newfound strength and manages to tear through Noodle Burger Boy's mech armor with ease. Noodle Burger Boy is forced to escape from Hiro. Hiro feels empowered by the shirt and decides to keep it on to help with Aunt Cass and other people. However, Hiro soon finds he is unable to control the shirt's strength, and he winds up breaking things by touch. Hiro tries to remove the shirt with Wasabi and Baymax's help but their efforts only make the shirt's hold tighter. Hiro goes to Fred's mansion believing Fred would offer some help, though even Fred is unsure of what to do. Once Fred leaves his room, his father, Mr. Frederickson, appears on Fred's monitor and finds only Hiro. Hiro learns that Mr. Frederickson once had a similar problem of trying to obtain superpowers through enhancing himself. Frederickson tells Hiro that he only needs to find his true strength from within.
Later, Fred invites the team to meet at the pier. Right when the team arrives, a gigantic Kentucky Kaiju rises from the water and reveals Fred inside the beast's head. Fred explains that he had a life-size Kentucky Kaiju robot commissioned. Suddenly, Noodle Burger Boy attacks Fred and hijacks the mech using a CPU Robot, which switches Kentucky Kaiju into battle mode and it heads into the city. Big Hero 6 then suits up to fight Kentucky Kaiju, but their weapons prove ineffective against the beast's superior strength and size. Hiro jumps into the cockpit to take out Noodle Burger Boy, only to discover the robot has already left while Kentucky Kaiju is now operated by the CPU Robot. Hiro is then forced out and nearly stepped on by the beast but Hiro is able to hold it back with his strength, although the overwhelming force of the beast causes the Nano-Dex to shut down. Hiro sees a billboard with Mr. Frederickson and, reminded of Mr. Frederickson's advice, launches himself towards the billboard. Kentucky Kaiju walks towards him preparing to attack, but it steps on high-voltage power lines, electrocuting the robot and destroying it.
The rest of Big Hero 6 reconvene with Hiro while the boy searches the robot's remains for the CPU Robot. As the team wonders where the device came from, Hiro realizes that the incident with Globby was a plot to manipulate Hiro, thus someone else must have been behind both attacks. Obake, still observing the team from his cameras, explains to Globby and Noodle Burger Boy his true plan was to test Hiro's intelligence and now he knows how high Hiro's intelligence is.
- The line Obake quotes "Our doubts are traitors, and make us lose the good we oft might win, by fearing to attempt" is from William Shakespeare's play Measure for Measure.
- The episode is likely a homage to the Kaiju film genre.
- Kentucky Kaiju makes its physical debut in this episode, but had made cameos and was referenced in previous episodes.
- The scene where Hiro builds his nano suit references the scene where he built Baymax's first armor in the film.
- Fred creating and piloting a giant kaiju creature is almost similar to his comic book counterpart in which he surrounded himself with a giant kaiju aura.
- By the end of the episode, Hiro's armor is destroyed and has a plain white shirt instead. However, in one of the shots after Fred wakes up, Hiro is seen wearing his full default armor again (with the red linings, rather than the purple nano-dex ones seen throughout the episode), then in the next scene it switches back to the white shirt.
- A billboard with Mr. Frederickson's image reads Frederikson Shipping. This was likely just a spelling mistake, though the billboard is seen in future episodes without being corrected.