At the Ito Ishioka Robotics Lab, Go Go and Honey Lemon are having a ping pong match against a robot built by Hiro, while Wasabi, Hiro himself and Baymax are watching. Suddenly, Fred interrupts them because a fire was started in a Tiki Torch factory and could be expanded to other inflammable places nearby. The team hurries to Fred's limo and go to his house for their suits, but upon arriving see they aren't there and remember they left them at Honey and Go Go's place. They get in the limo again to be taken to their apartment, though now have trouble gearing up because they can't find some of the parts. Finally, they go to the scene but upon arriving see that firefighters had cleared the fire already and tell the team they're late.
Following this, the team meets at Lucky Cat Café where Aunt Cass shows the team Mochi's new trick of clapping slowly. Honey Lemon records him and uploads online. Fred then tells his friends that he got two tickets to see the Maximum Insane Obstacle Challenge live and could invite one of them. Hiro immediately tells him he can't go as he has to work out their gear-up issue. Wasabi makes up an excuse and runs away, while Go Go straight up says no. Honey Lemon mentions she'll do a sticker party, and Go Go then says she'll go with Fred because she dislikes Honey's sticker parties. At the show, the first contestant picked fails his first challenge and splatters Go Go and Fred with soy sauce from the challenge. The next challenge picks Go Go as the contestant, but she refuses to do it and look like an idiot in front of millions.
Meanwhile, Hiro takes Wasabi, Honey Lemon and Baymax to the other side of the city in a field to try out a new suit delivery system he invented. The system calls their suits right at them, but gives each one the wrong armor and Hiro gets Wasabi's, Honey Lemon gets Baymax's, Baymax gets Hiro's and Wasabi gets Honey Lemon's. The next day Honey Lemon shows Go Go the video of Mochi clapping slowly which was rising in popularity and unadvertedly taking Mr. Sparkles' Maximum Insane Obstacle Challenge's popularity spot. Though Mr. Sparkles continues to make the show, less people watch it and progressively becomes less relevant.
Hiro takes Wasabi and Baymax for another suit delivery test, but the machine meant to give their suits malfunctions and shoots the armors at them. Wasabi tells Hiro he has an inventor's block, and later back at Hiro's room he keeps trying to come up with an idea but is unable to.
Mr. Sparkles tried entering a building but was not allowed in by Felony Carl, then Aunt Cass passed by with Mochi (who was now known as "Slow Clap Cat") riding her bike and everyone admired the cat taking pictures of him. Carl called Mr. Sparkles and nobody and Sparkles became furious that his fans were "stolen" and decided to take revenge against Mochi. Back at the Ito Ishioka Robotics Lab, Hiro was becoming more worried about his block thinking he'd never overcome it, but Wasabi told him to relax and meditate with him. While meditating, Hiro imagined himself working on more solutions and Wasabi said that was not the point of meditating.
Bluff Dunder interviewed Cass about Mochi but while both were distracted a robotic mouse sent by Mr. Sparkles entered the set and lured Mochi away, being taken by Sparkles who later put him in a rocket and announced a new challenge that someone had to complete or else Mochi would be launched to space. Fred showed the announcement video to Big Hero 6 at Lucky Cat Café and the team went outside where Hiro would demonstrate yet another suit delivery system; this time it was a voice integrated command that Fred nicknamed "VIC". It however was flawed and sent their suits to the ocean rather than the Café. Forced to work without their suits, Hiro told Baymax to go with Aunt Cass and prevent her from finding out what happened to Mochi while the rest of his teammates would go and attempt to complete the challenge. Hiro himself went to work in a new robot to save Mochi in case they failed.
The four heroes went to Sparkles' show set where Fred tried the challenge first and failed immediately, followed by Wasabi who lasted longer but still lost, then Honey Lemon who managed to get through the challenge until Mr. Sparkles flipped a platform, making her fall and lose as well. Aunt Cass went spreading flyers while Baymax stopped her from seeing screens showing the ongoing challenge. Last contestant was Go Go, who finished the challenge even with Mr. Sparkles' cheating. The evil Mr. Sparkles however did not care that she finished and launched the rocked regardless, then escaped on a giant robotic chicken.
Hiro managed to get to the set soon after Mochi was launched and called his newest invention, Skymax, to go and retrieve the cat. Once Skymax brought back Mochi, his reunion with Aunt Cass was recorded and also posted online where it became a hit video too. Next day the team met again at Lucky Cat Café, where Hiro reprogrammed Skymax to deliver their suits and introduced it to the team.
On the other hand, Mr. Sparkles saw the video where he kidnapped Mochi had gotten over ten million views and enjoyed the fame, even though he was now a searched criminal having a large "Wanted" poster of himself on a building right behind.
- Mr. Sparkles (debut)
- Some of the video titles shown on Mr. Sparkles' phone when he looks at the charts are parodies of real-life popular internet videos.
- The website "MeowTube" is an obvious parody of YouTube.
- One of the cats seen in the website resembled Donald Trump.
- Though this is Mr. Sparkles' debut, he previously had a cameo in "Baymax Returns".
- Hiro wears Wasabi's armor as an accident, but later gets to actually use it in "Killer App".
- The eyes on sign Mr.Sparkles resembles the eye design used in My Little Pony: Friendship is Magic, and references the use of eyes to visually common in cuteness.
- Mochi is facing the opposite way in the scene before he slow claps.
- Go Go loses one of her shoes while doing Mr. Sparkles' test, but when she leaves the building after Mochi is launched, she is wearing both. It is also seen in every other following shot that shows her full body.
- There were three civilians watching Mr. Sparkles' show at Lucky Cat Café, but at the same time the same characters were present during the show sitting near Go Go and Fred.