Professor Granville, Hiro, Go Go, Honey Lemon, and Wasabi have been invited to Sycorax, because Karmi is now interning at the company, much to Hiro's jealousy. They are welcomed by Liv Amara, and her assistant Chris, who gives them a tour of the Sycorax building. There are bio-metric scanner grounds, hovering assistant robots, and their state-of-the-art GenTech lab, which is temporarily being used by Karmi until her real lab is built to her specs. Overwhelmed by his jealousy, Hiro decides to get an internship at Krei Tech Industries. Krei is at first not interested in having an intern until Hiro bribes him, taking advantage of his rivalry with Liv Amara.
Meanwhile, it is revealed that Trina and Noodle Burger Boy had survived the destruction of Obake's underwater lair. However, Noodle Burger Boy is malfunctioning and goes "home" for repairs, abandoning Trina who still a severed head and body. He returns to Noodle Burger, and since the manager cannot fix him he proceeds to go on a rampage and breaks everything in the restaurant.
Big Hero 6 gets the news of Noodle Burger Boy's return and decide to go on day patrol. Hiro backs out as he is staring his first day as an intern. Unfortunately, the internship at Krei Tech was not what he expected. Krei has Hiro pick up his drycleaning along with a cow costume. To make matters worse, he bumps into Karmi who laughs at him. He was being used as an errand boy.
Fred and Honey Lemon are on patrol, and soon find Noodle Burger Boy after following a trail of pickle juice that leads to an alley. They find him in an alley, walking into a while, still glitching. When he takes notice of Fred and Honey Lemon, he starts shooting pickles at them. Noodle Burger Boy runs out of the alley, causing collateral damage before escaping on a trolley. He is later confronted by Go Go and Wasabi, and continues to go crazy, shooting his lasers. Wasabi blocks his attacks with his plasma blade, redirecting them back to Noodle Burger Boy, cutting off one of his legs. Noodle Burger Boy escapes, but Go Go and Wasabi figure out where he is going, Krei Tech which is "home" to him.
At Krei Tech, Hiro is at is breaking point and wants to quit being Krei's errand boy. Just then, Noodle Burger Boy bursts into the office. He states that he is malfunctioning and is in need of repairs, so he has come to Krei Tech to be fixed. He kidnaps Hiro, Baymax, and Krei and brings them to the Noodle Burger factory, where he threatens to fry Krei unless Hiro fixes him. Big Hero 4 arrive at Krei Tech, only to find to discover they are too late to save Hrio, Baymax, and Krei. Trina then shows up in a souped-up robotic amalgamation and fights them, taking them all out. Racing against the clock, Hiro is still trying to fix Noodle Burger Boy as a tied-up Krei is moved closer to the oil vat. Hiro manages to fix Noodle Burger Boy and tries to remove the Obake chip only for Trina to blast into the room to retrieve her "brother". Hiro uses an ultra powerful magnet to incapacitate Noodle Burger Boy and Trina, escapes and saves Krei before he get incinerated. However, Trina and Noodle Burger Boy escape. The next day, Krei pays Hiro a visit at the Lucky Cat Café. He thanks Hiro for saving him, and says he wants him for his inventions. Hiro attempts to back out, but since he signed a contract Krei owns him for the next year.
- 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
- Lucas Neff as Noodle Burger Boy, Brad
- Haley Tju as Karmi, Passer-by
- Christy Carlson Romano as Trina
- Ben Feldman as Chris
- Diedrich Bader as Bluff Dunder
- Jenifer Lewis as Professor Granville, Sarah
- Laura Silverman as Judy
- Alan Tudyk as Alistair Krei
- Kari Wahlgren as Brooke, Soft Comuter Voice
- Mara Wilson as Liv Amara
- Fred refers to the events of season one as "Phase One" and his predetermined events of season two as "Phase Two" of the "Big Hero-verse". This is an obvious nod to the Marvel Cinematic Universe and how it splits its films into "phases".
- Fred's middle name, Flamarion, is revealed in this episode.
- The name of Krei's assistant is revealed to be Judy in this episode.
- Even so, she is still credited as "Krei's Assistant".
- When the main characters take a tour of Sycorax, the group is given identification cards that list everything including their full names. Despite this, Wasabi, Honey Lemon and Go Go Tomago's names are listed, even though it is established that these are just nicknames.
- September 23, 2021 (Poland)
- March 29, 2021 (Portugal)
- July 19, 2021 (Romania, Bulgaria, Czech, Hungary)