At Frederickson Manor, Fred and Hiro are playing video games when suddenly they hear Fred's mother screaming. They run to investigate, only for it to just be her screaming for joy at a cute puppy video. Liv Amara is there too, and Mrs. Fredeickson is looking to invest in Sycorax. She also asks about Liv's progress on curing Orso Knox. Liv says they are two to three weeks from a breakthrough, which relieves Mrs. Fredeickson. However, it makes Hiro suspicious. He decides to investigate this further, finding out that this is the exact same thing she said on an interview two months ago. Hiro, Baymax, and Fred visit Karmi at Sycorax, and convince (manipulate) her into finding out about Orso. She does not get a chance to ask why, especially when Fred accidentally destroys a bunch of virus cultures.
Karmi tries to find info on Orso in the company's database, but the folder the information is on is locked out. Karmi visits Liv in her office and ask her about the file. Liv responds with that the file is only for her Knox team. Karmi tries to convince Liv about helping but Liv turns her down. Karmi returns to the lobby to find Hiro, Fred, and Baymax waiting. Karmi brings them into her lab to avoid Liv. Hiro de-crypts the Knox File and opens it. They find out he is in Sub-Level nine and that he is experiencing some thing about gene sequences and over-expressions. Karmi says she can fix it but she does not want to risk her internship. Hiro convinces Karmi and they go down to Sub-Level nine, which happens to contain a lot of organs in tubes, along with Orso Knox, who is in a cage. As Karmi starts working on the console, Hiro notices that Knox is not talking like. Liv, who walks in, says he has becoming less human. Liv is disappointed in Karmi, but when she finds out what she did works she decides to let Karmi keep working on it. Liv leaves for a meeting, but for some reason brings Fred with her. After Liv and Fred leave, the cage for Orso is disabled allowing him to get out.
They try to get out through the elevator, which is now disabled. Hiro notices Orso has escaped his cell, alerting Karmi. They start to search for Orso, and he finds them. Orso causes some damage in the lab while Hiro, Karmi, and Baymax attempt to escape him. Meanwhile, Sycorax goes on lockdown, which cannot be overridden. So, she goes off to gather her team while Fred gather Big Hero 6. Karmi, Hiro, and Baymax run into a room with Orso in hot pursuit. Hiro disables the mechanism and goes with Baymax to trap Orso back into his cell and leaves Karmi in the room by herself. She goes to work on a cure for Orso. Big Hero 6 attempt to get in the building but cannot due to the various chemical properties Titanium has. Meanwhile, Hiro and Baymax find a fridge that contains Orso’s food, which they use to lure Orso into his cell. They almost manage to get Orso into his cell, only for Hiro to step on some meat and alert him. Baymax tries to stop Orso from chasing after Hiro, but fails. He captures Hiro and flees. Meanwhile, Big Hero 6 manage to cut into the titanium, only for Orso to break through, with Hiro in tow. Sycorax goes out of lockdown and Liv says they might have to kill Knox. Just then, Karmi shows up, saying she can cure him, only to be shut down by Liv.
Orso is running around the city, causing surprisingly as little damage as possible. Hiro manages to escape Orso’s grasp but falls of a ledge. However, Orso saves him, which makes Hiro realize that he is not trying to hurt people. Orso proceeds to raid trash cans in the alleyway, only for a cat to come up and scare him. This leads to a chain reaction of traffic jams, leaving Orso to burrow into the subways of San Fransokyo. Big Hero 6, suited up in ultra armor, are on the search for Orso. Baymax's scanners are slightly broken but he can find Knox's heat signatures prompting the team to go to the subways. Hiro is already in the subway systems, looking for Orso. The team eventually enter the subways to confront Knox, hearing his roars through the subway tunnels. They encounter Knox and proceed to attack him, Knox mostly just runs through the tunnels not directly hurting anyone. The team manage to incapacitate Knox, only for Hiro to stop them before they severely hurt him. He cautions everyone not to make any sudden moves or loud noises, but with the build-up of dust Wasabi sneezes causing Knox to lash out and start a cave in. A piece of cement begins to fall on Hiro but is stopped by Knox before he passes out. They bring Knox back to Sycorax and successfully cure him. At a press conference, Liv says that Orso has graciously invested in Liv’s future, but after that Liv tells Orso that she can turn him back into a monster any time she wants.
- Ryan Potter as Hiro Hamada
- Scott Adsit as Baymax
- Génesis Rodríguez as Honey Lemon
- Khary Payton as Wasabi
- Jamie Chung as Go Go Tomago
- Brooks Wheelan as Fred
- Haley Tju as Karmi
- Mara Wilson as Liv Amara
- Fred Tatasciore as Orso Knox
- Ben Feldman as Chris
- Diedrich Bader as Bluff Dunder
- Susan Sullivan as Mrs. Frederickson
- When Hiro was asking Karmi about Orso Knox, the Sycorax logo wasn't present on Karmi's lab coat until when Fred destroyed her viruses.
- This episode confirms that Liv Amara is behind Orso Knox's transformation.
- Karmi reveals that she does care about Hiro to a certain degree.
- This episode is the first appearance of the upgraded armor.