The episode begins with Nicole driving on the highway, taking Gumball, Darwin, and Anais to school. The highway traffic is blocked, but Nicole, deciding not to wait for the traffic, pulls her kids out of the car, and hops her way to school. Nicole finally arrives at Elmore Junior High, dropping her kids off. Suddenly, at that moment, a shady figure arrives, and states to Nicole that it's been a long time. Nicole turns around and sees her. The figure reveals herself as Yuki, Nicole's old friend. Yuki challenges Nicole to a fight, but Nicole refuses and walks away.
The children are surprised by this, and spend the school day wondering why Nicole walked away from the challenge, whether it was out of fear, or an ulterior motive. At the end of school, Nicole picks them up (with her car wrecked by Yuki), and takes the whole family out for grocery shopping, looking quite sad, despite Richard trying to cheer her up. Suddenly, Yuki appears and starts to flirt with Richard to taunt Nicole, but she still refuses to fight. The next day, Nicole has to endure a whole day of Yuki's taunting at the Rainbow Factory, such as taking her working area, ruining her lunch and coffee breaks, and interrupting her work.
At school, the siblings are still baffled by their mother's situation. However, Masami, Yuki's daughter, explains it to them. She reveals that Nicole and Yuki were childhood friends, and studied martial arts together under Yuki's father. The two were prodigies and best friends, until the final tournament came, where they were forced to fight each other. Nicole came out as the victor due to her fury. Yuki left the United States in shame, and Nicole quit pursuing martial arts after losing her friend. In Japan, Yuki trained excessively until she was ready to face Nicole. Now, she returned for revenge, and to regain her honor. Then, Masami gives them a letter from Yuki to take to Nicole. At home, Nicole reads the letter where it says that she will lose her job and her house unless she accepts Yuki's challenge. So, she storms out in a rage to confront Yuki.
Nicole and Yuki meet at the gym, and begin their epic anime-styled battle as their children look on. After Yuki is seemingly defeated, Nicole offers her a chance of redemption. But Yuki is unable to swallow her pride and attacks, resulting the roof to collapse and trapping their children. The rivals put their differences aside and free their children. Afterwards, Yuki apologizes for everything and reveals that she did it out of jealousy—Nicole also apologizes and tells her not to worry. The two then hug and lament how much they missed each other. The two mothers take their children and hop their way back to their homes, ending the episode.
When Masami, Gumball, Darwin and Anais are trapped, it appears very similiar to the scene in Barefoot Gen (or Hadashi no Gen) where Gen's dad, brother and sister are trapped, and Gen and his mother tries to save them from the fire.
The scene where Yuki destroys Nicole's car is a reference to the Bonus Stage from Street Fighter series.
The outfit Yuki wears during her fight with Nicole closely resembles Jeanne from the Bayonetta series, specifically the outfit she wears in Bayonetta 2, as they both wear Red jumpsuits, have white/silver long hair and a bang.
Despite being similar appearance wise, both characters also play the role of childhood friend/rival who was defeated and determined on regaining honour, though later becoming close allies again, in their franchises.
[The episode begins with Nicole and her kids speeding along a highway. In the car, the kids are trying to hang out and eat cereal at the same time. Finally, they manage to put their liquids into their food]
Gumball, Darwin and Anais: Ah.
Anais: That's better.
[Nicole's car then stops hurriedly, causing their food to splatter the windshield. It is then shown a traffic jam]
Nicole: Come on, we're going to be late.
[Nicole begins jumping car over car to hurry her kids to their school]
Pantsbully: Hey, are you crazy you-
[Nicole shows her fiery eyes at him, causing him to break into a little tune.]
Nicole: We need a shortcut.
[The next scene shows the bank area, with police outside waiting for an expected thief]
Doughnut Sheriff: Put your hands on your head and come out of the building!
[Someone tries to open the bank doors, however it would not budge]
Doughnut Sheriff: Sorry, I meant: come out of the building and put your hands on your head!
Nicole: Get out of my way, we're late for school!
[The bank entrance explodes, with Nicole rushing by at break-neck speed]
Doughnut Sheriff: Hey, Mrs. Watterson what about the- [A bag of money hits him] Money...
[The kids reach the school right as the bell rings]
Nicole: [Mouthing] Have a nice day!
Anais: We traveled faster than speed of sound, give it a second.
Nicole: [Voice] Have a nice day!
Anais: There you go.
Gumball: Heh, thanks Mom.
[The kids stumble up the stairs, as if they twisted their legs]
[Behind her, stands a tall and slim figure. It greets Nicole]
Yuki: Hello, Nicole. I've waited a LONG time for this.
[Nicole focuses on the slim object]
Nicole: I'm sorry, I really can't see you. Could you just, take a step forward?
[The slim object takes a step forward, revealing herself]
Nicole: [Gasps] Yuki!
Yuki: Yes, Nicole. I have returned-TO FIGHT!
Gumball: Ok, everybody leave or cover your eyes! This scene is gonna be rated "R" for abundance of outrageous gore!
[Students walk away or enter the building; The kids watch behind the school door; Nicole walks towards Yuki]
Nicole: I'm sorry, Yuki, you win. I don't want any trouble.
[Yuki slaps her right hand]
Yuki: You're not half the person I used to know. Your butt, on the other hand, is TWICE the size!
Anais: O-M-G. She just called mom fat.
[Nicole takes a deep breath in]
Nicole: It was nice seeing you Yuki.
[Nicole walks away]
Yuki: COWARD! Where is your honor?! FIGHT ME!!! FIGHT ME!!!
Gumball: What the actual what?
[School bell rings]
Darwin: I can't believe Mrs. Mom just walked away!
Gumball: Maybe she walked to that woman's house and ate her pets!
Anais: No.. that was weird. She looked like she'd seen a ghost. Maybe Mom is... afraid.
Gumball: Hm, weird. I never thought I would hear the word "mom" and "afraid" in the same sentence.
Darwin: Unless, the sentence was "I'm really afraid of your Mom."
Anais: Or, "You should be afraid of our Mom."
Gumball: Or, "The test results just came back, I'm afraid your Mom is 90% water, she is 90% anger. Uh, so what happened?
Nicole: Oh, it was nothing. Just an old-school friend.
Gumball: I meant, what happened to the car.
Nicole: Oh, that?
[Nicole flashbacks, showing Yuki repeatedly smashing various parts of Nicole's car]
Nicole: Here we go.
[Due to the damage Yuki has made, the car moved slowly]
[At the shopping district supermarket]
[Richard tries to cheer Nicole up by putting various vegetables all over his head]
Richard: Nicole? I think we need better toothpaste. [Nicole looks at him] What? Is there something wrong with my hair? Do I look better with a hat? It goes really well with my eyes.
[The whole family laughs]
Richard: Come on you. [Richard hugs Nicole] What's wrong?
Richard: Good, you keep smiling, or I'll have to use my secret weapon.
Nicole: What's that?
Richard: [Has melons on his butt and bangs them] Butt, butt, butt, butt, butt-butt! Butt, butt, butt, butt, butt-butt!
[The whole family laughs but then Yuki shows up]
Yuki: What is so funny?
Richard: [Gasps; all the vegetables come off him] Yuki Yoshida.
Yuki: Hello, Richard. [Walks towards Richard] You look more handsome then ever. What's your secret?
Richard: Uh, I got old and fat...er.
Yuki: What's a man like you, doing with a woman like her?
Richard: Shh! I don't think she knows she could do better.
Yuki: [Laughs] Oh, Richard, you always were so funny. And doughy. [Squeezes his arm]
[Richard tries to escape from Yuki but kicks her legs up stopping him]
Yuki: Somebody pinch me, I must be dreaming. [Anais punches Yuki] Ow!
Anais: Oh sorry, I thought you said "punch," not "pinch".
Nicole: There is no point, Yuki. I refuse to fight you.
Yuki: What kind of woman would do nothing in the face of such dishonor?! [Nicole and Yuki glare at each other]
Masami: Mom? Can we go, please?
[Yuki scoffs and walks away. She then flips a shopping cart]
Crocodile Woman: That was mine! [Yuki glares at her] Never mind.
[Scene changes to the Rainbow Factory, where Nicole is about to go to her desk but Yuki is already there]
Yuki: My husband owns this factory, so this is my spot now. Yours is over there. [Points with her legs to small squished desk]
[Nicole goes to the small desk and sighs. Yuki then starts taunting Nicole at work. Yuki ruins her lunch and coffee breaks. Nicole goes to her locker and sees gum when she's trying to open it]
Nicole: To be honest, compared to the rest of the stuff you've been doing, this is pretty tame. [Nicole opens her locker, only to find out it's covered in gum] Ugh!
[Nicole runs to the elevator but Yuki closes it. Nicole is about to take the stairs but Yuki opens the elevator. Nicole runs to it again but Yuki closes it. It opens again and Nicole goes in but Yuki presses all the buttons]
Nicole: Oh, come on-
[Nicole walks home. In front of the house, Yuki spelled "COWARD" with fire. Nicole enters the house and body slams herself on the sofa. The kids look at her. Scene changes to school as the bell rings]
[Gumball and Darwin stammer as they try to come up with something to say; they then look to Anais]
Anais: Sorry, guys.I don't know what's going on with mom and this woman, either.
Masami: [Masami appears behind them] I do. [They all look at her] They have history. Once upon a time, Nicole and my mother were friends, studying karate under my grandfather. Separately, they were strong, but together, there was nothing they could not do. Until the Elmore Kumite, a ruthless martial arts tournament. Nicole was mother's kohai, her protégé. But as the tournament progressed, they had to face each other in the final fight. My mother should have won easily, but your mother's fighting skills allowed her to triumph. Dishonored before her sensei, my mother left America in shame. Nicole gave up the way of the Bushido out of sadness for losing her friend. Back in Japan, my mother trained all these years for her next fight, and now she's back to regain her honor.
Gumball: [Narrating] But mother will not accept this fight.
Darwin: Her heart is too pure to hurt a friend.
Gumball: [Anais and Masami look at them] Her soul is too noble.
Anais: Can you stop that, please?!
Gumball and Darwin: Sorry.
Anais: They're right, though. Mom won't fight a friend.
Masami: She may not have a choice. [Hands them a letter]
[Back at the Watterson's house, Nicole reads a note, crumples it up and throws it on the floor. She then heads towards the door]
Nicole: Your mother has to take of some unfinished business. Don't follow me. It's too dangerous. There's leftover ham in the fridge and some tater tots in the oven. Do not microwave them. They'll go soggy! [Slams the door]
Anais: [Uncrumples the note on the floor and reads it. Anais gasps] Yuki threatened to get mom fired and lose the house unless she fights. We've got to stop them.
[Scene changes to the gym; Yuki is on the floor and Nicole comes in. Nicole and Yuki start to fight in an epic-anime-styled battle. Masami is already there while the kids enter]
Masami: What took you guys so long?
Darwin: Takes ages to get anywhere on these legs.
Gumball: Are you also here to stop the fight?
Masami: Yeah, but then I realized I'd probably get annihilated trying. So...[Grabs some popcorn]
[Nicole and Yuki still fighting]
Yuki: You fought well, Nicole-san, but I've been training my whole life for this moment. Let me show you what I've learned.
[Yuki attacks Nicole with an energy blast]
Yuki: Yah! [Nicole blocks it] Impossible. How?
Nicole: I have been through the most grueling training on the planet.
Yuki: Which school taught you? Was it Hokuto? Was it Konoha? Or was it Mr. Miyagi?
Nicole: No, it was the school of life. I have raised three kids and one husband. [Nicole gets angry and starts attacking Yuki]
[Yuki fights back as the kids watch them; Nicole manages to beat Yuki as she falls to the ground; Nicole stares at her and Yuki gets scared; Nicole reaches her hand out]
Nicole: Let's just be friends.
Yuki: [Yuki gets angry and tries to attack Nicole] I don't need your pity!
[Nicole dodges Yuki's energy blast causing the roof to collapse on the kids; They all scream, while Yuki and Nicole run to them]
Nicole: Kids! It's gonna collapse! Aah!
Yuki: [Tries lifting a bar of metal to save them] I can't do it!
Nicole: But, together, we can!
Both: [Yuki and Nicole karate chop the piece of metal] Hyah!
[They both grab the kids and run out of the gym]
Nicole: Come on!
[They're all out of the gym and the kids make horrified faces]
Yuki: I'm sorry, Nicole. I was just... jealous. [Yuki starts crying]
Nicole: Well, you shouldn't be. You always had the best hair and house and car and butler and ponies and pony butlers.
Yuki: I can't believe I tried to annihilate you.
Nicole: I tried to annihilate you first. Don't worry about it.
[Nicole and Yuki hug while sobbing]
Nicole: I missed you!
Yuki: I missed you too!
[They wipe away their tears]
Yuki: [Sighs] Come on, guys.
Nicole: Let's go home.
[The kids gasp and get scared]
Yuki: Oh, please! It was just a little argument between friends.