The episode starts with the cheerleaders of Elmore Junior High spending their lunch break practicing on the field. Gumball is spending his own time spectating over them (Penny, in particular), taking a reluctant Darwin along. At first, the day appears to be sunny, with the cheerleaders performing their routine flawlessly and Gumball rooting for Penny.
Darwin snaps Gumball out of his euphoria, making him realize the rainy condition, the routine gone wrong and his cheering over Penny's mishap. This happens in time for him to see Leslie walking Penny off and hugging her, causing the jealousy in Gumball to intervene. Jealousy assumes direct control of Gumball's body and angrily races off towards Leslie, blowing through many obstacles along the way. Unfortunately, he uses too much of his energy on the obstacles, passing out upon reaching Leslie and Penny, who have walked off without noticing him.
In the cafeteria, Gumball spies on Leslie and Penny, whose envy once again assumes control over him and causes him to scornfully mock Leslie. He charges in to attack Leslie, who easily brushes him aside and walks away with Penny. Furious at his own spiteful emotion, Gumball fights back for his body, but is overpowered. He is knocked out by his own limbs.
With Gumball unconscious, his body is under the unadulterated influence of his Jealousy. He attempts to frame Leslie for the theft of a trophy but fails for not concealing his tracks. In the wake of the incident, a trail of glass behind was left behind after Gumball had smashed the trophy case, Leslie's locker had already been pried open after he himself attempted to place the trophy in it, and in his own locker are herbicides, vandalized pictures of Leslie, and the crowbar Gumball used to force Leslie's locker open. Upon being caught, Jealousy gives a dazed Gumball his body back, leaving him to take the fall.
Everyone involved gets called into Principal Brown's office, where Gumball attempts to apologize to Leslie. His Jealousy intervenes and spews a long string of insults at Leslie. Believing to be locked away in prison as a result, Gumball sadly resigns to his fate, but Principal Brown notifies him that he will not be incarcerated. Upon hearing this, an ecstatic Jealousy repossesses Gumball and attempts to flee to Mexico. His plan is foiled by his inability to open the door, repeatedly running into it until knocking himself out. Gumball, lying knocked out on the ground, agrees to make amends with Leslie.
The two try to bond with a walk in the park. Gumball benignly offers Leslie a seat on a shady bench, which Leslie gingerly accepts. All is well until the trap set by Gumball's Jealousy is triggered - Leslie's spot is slathered with superglue, allowing Gumball to unleash snails and other herbivorous insects upon him. After a few mildly clever remarks, Gumball departs, leaving Leslie to die.
At the school cafeteria the next day, Penny and Darwin remark on the friendship formed between Gumball and Leslie. Bursting through the cafeteria doors is a naked and partially eaten Leslie, calling Gumball insane. Penny immediately rushes to his side, prompting Gumball's Jealousy to return. Gumball, with no traces of his former self, pounces on Leslie and brutally rips his petals off one by one. Darwin rushes over and, with Penny's help, restrains a feral Gumball from hurting Leslie further. By then, everyone notices that Gumball is not himself. Carrie formulates a plan and leads them all to her house.
Knowing full well that Gumball's Jealousy had gotten the better of him, Carrie has called everyone to her room to perform an exorcism. They put Gumball in the center of a circle of candles and occult markings while chanting "Jealousy be gone..." repeatedly. Much to Carrie's surprise, the exorcism is successful, and the Jealousy is expelled from Gumball's body and manifests into a lumpy green ball of ectoplasm. Penny steps into the circle to try to help Gumball but breaks the protection ward by doing so, releasing Jealousy from his prison.
He immediately wreaks havoc on the room, trashing anything and everything that he envies and possessing Leslie, Carrie and Darwin in order. He soon declares an ultimatum: if he cannot have Gumball, then nobody can, and prepares to explode. The only way to be rid of him is if Gumball overcomes his envy of Leslie. But he cannot so long as Penny and Leslie are dating, to which Penny responds that they're not dating, they're cousins. Now that Gumball is no longer jealous of Leslie, Jealousy disappears.
The five kids lie exhausted amidst a pile of Carrie's belongings. Carrie gives Gumball a friendly punch in the arm, which causes Penny to blurt out a similarly-lengthy insult at her. Everyone is shocked and say "Wow" in unison, ending the episode.
This episode reveals that Darwin is absolutely satisfied with his life to the point that he is immune to jealousy. This is somewhat contradicted in "The Roots" and "The Night," where Darwin greatly desires a larger fish tank to sleep in.
This was the second time Leslie is shown without his flower pot. The first time was in "The Party." However, he was not pixelated in that episode. The third time is in "The Boombox" where he is again pixelated.
In Latin American airings, Gumball (who was possessed by Jealousy) said he was going to escape to Africa.
When Gumball tries to kick Leslie in midair, he yells out "Hadouken!," a reference to Street Fighter.
The circle of pepper used to isolate Jealousy during the exorcism is a reference to putting down a ring of salt. In some beliefs, a ring of salt is used as a protective barrier against demons and other spirits.
The part where Carrie, Penny, Darwin and Leslie try to exorcise Jealousy out of Gumball is similar to the scene in the 1973 movie The Exorcist.
The character of Jealousy being green and turning its victims green is a play on the words "green with envy."
Leslie with a vacuum is a homage of Ghostbusters series.
The AB/CD logo on the vaccum references the AC/DC band logo, as the red background color, lettering, and lightning bolt between the letters are the same.
During the investigation of Gumball's locker, when a crowbar falls out, Gumball is seen doing the popular fad "Pokerface."
Penny's relationship with Leslie is a reference to how real life peanuts are shown to grow once the flower it is connected to starts blooming.
When Leslie said, "Well, someone found it entertaining," one of the frames in the shot just shows the background, but no characters.
When jealous Gumball is running through the football track, Bobert is seen running along with other students in the rain. However, in "The Robot," Bobert shorted out when he got wet. Also, Teri helps Penny when she falls, but she could not have stayed in the rain because she is made of paper.
When Tobias is seen walking in the background in a scene in the cafeteria, he has his Season 1 design.
On the DirecTV captions, when Penny says, "Fat-faced people have feelings too, you know, Gumball," it directs that Darwin says it.
When it is shown that Gumball put the trophy in Leslie’s locker, glass footprints are seen. However when the ground is again seen, the footprints are nowhere to be seen. In the next scene when Carrie speaks, the footprints are again seen.
When possessed Gumball wheezes, he wheezes similarly to normal Gumball, instead of his lower-pitched voice.
When Penny gets possessed by Jealousy, the details on her shell go missing.
Carmen is seen in her Season 1 design when in the cafeteria.
[Gumball and Darwin sitting in the bleachers at Elmore Stadium. It's a sunny day and the cheerleaders are singing while Penny performs a move]
Cheerleaders: One, two, three, four, five, we are Elmore Junior High! Six, seven, eight, nine, ten, spin around and start again!
Gumball: Woo-hoo! That's my girl!
[Penny blows Gumball a kiss and he catches it, and pats it on his chest]
Gumball: Right next to my heart, baby.
Darwin: Dude, what are you doing?
Gumball: What's the problem, can't a guy celebrate when his cheerleader girlfriend lands an amazing flip on a beautiful sunny day?
Darwin: Okay, I don't know what kind of reality you're living in. First of all, this isn't a sunny day. [Lightning fills the screen with light, rain starts pouring and thunder starts roaring] Secondly, that move went wrong and you cheered. [Takes a bite of his sandwich]
Carmen and Teri: Oh, Penny, are you okay?
[Carmen, Teri and Leslie help up Penny, who is upside down on the ground]
Penny: [Grunts] I face planted so hard, I've got grass on my tonsils.
Leslie: Well, someone found it entertaining. [Leslie and Teri look at the camera angrily]
Darwin: And finally, she's not your girlfriend.
Gumball: What? Well, then how come she blew me this kiss?
Darwin: That's ketchup, [Gumball looks at the ketchup stain] you just smeared it all over yourself.
Gumball: What the-! What's going on?
Darwin: What's going on, is you've dragged me here to eat my lunch in the rain, so you can gawk at Penny like you do every day, even though you guys aren't even boyfriend and girlfriend!
Gumball: Oh, yeah, well, you look like a s-swollen...traffic...cone!
Darwin: Sorry, dude, I didn't mean to offend you, I'm not saying it won't happen. But right now, you've got some competition. [points at Leslie helping Penny walk back to class].
Leslie: Come on, now, let's get you back inside.
Gumball: Who? Leslie? Nah, they're just friends. [Looking at Leslie again]
Penny: [Hugging Leslie] Oh, Leslie, what would I do without you?
Jealousy: [Thinks that Penny and Leslie are dating] And that's how it starts! Soon he'll be her boyfriend and you'll be history.
Gumball: No, it's not like that, he's a nice guy.
Jealousy: No he's not, and I'm gonna put an end to this, RIGHT NOW! [Starts running to Leslie while grunting]
Darwin: [Surprised] ...Wow.
Jealousy: [Runs through the hurdles, passing by Bobert and Jamie, knocking Tobias unconscious with a baton, grabbing a football and hitting all the Elmore football players, and finally, reaches Leslie] Penny...Leslie...
Gumball: STITCH! [Tired from all the running, Gumball passes out and sinks into the mud]
[In the school cafeteria, Leslie is talking to Penny about something]
Gumball: :[Spying on Leslie and Penny with binoculars] You see, there's nothing going on. They're just eating lunch and chatting.
Darwin: What do you think they're saying?
Jealousy: So how do you like my stupid pink petals and my fat yellow face [Leslie's lips are following the words] Oh, I'm so pleased you like it. I use it to steal GIRLS FROM PEOPLE!
Carrie: [Appears and flips her hair] Who are you talking about?
Darwin: Gumball is jealous of Leslie.
Carrie: Leslie! why?
Jealousy: Because he's trying to steal MY GIRL! [Barges into the cafeteria, leaving Carrie and Darwin shocked]
Leslie: You know, you should seriously consider becoming a carnivore.
Leslie: Because before it ends up on your plate, [Shows a picture of a carrot being peeled] this is what they do to vegetables!
Penny: Mm...humm... yeah. I'm not sure that baloney is such a good option though.
Leslie: Well, at least I'm not eating my own kind...[Leslie's voice turns blurry; Penny sees a possessed Gumball, but doesn't recognize him because he is distant; Gumball strangely runs towards them, but does not appear to get any closer]
Penny: Uh-huh. [Jealousy is still running towards them] Yeah.
Leslie: In cold water...[Jealousy is still running, when he finally arrives, he starts slapping Leslie's pot; Leslie pushes him away effortlessly]
Jealousy: [Tired] Curse this feeble body, you should work out more. [Continues slapping Leslie's pot]
Penny: [Looks at Gumball angrily] Gumball, what is wrong with you?
Jealousy: What's wrong with you [Slaps Leslie's pot three times], hanging out with this loser, instead of me.
Penny: Come on, Leslie, let's get out of here!
Jealousy: [jumps and attempts to kick Leslie] Hadouken! [Misses and falls on the ground]
Gumball: Penny, I'm so sorry.
Jealousy: No, I'm not!
Gumball: Shut up.
Jealousy: [Slaps Gumball] You're pathetic.
Gumball: [Slaps Jealousy back] You're pathetic, you insecure weirdo. [Notices his left hand being possessed] Oh. [Gets slapped and falls to the ground; he laughs nervously before passing out]
Jealousy: Looks like I have to take care of this myself!
Carrie: [Surprised] Wow.
Darwin: I know, I've never seen him like this before.
[In the school hallway, a possessed Gumball is talking to Principal Brown]
Jealousy: And the case is solved! Commissioner Brown, arrest this man. [Points at Leslie]
Nigel Brown: [Confused] What are you talking about?
Jealousy: The case of the stolen trophy, which I have just found in his conveniently open locker.
Leslie: Principal Brown, I think it's pretty obvious what's happened here.
Carrie: [Looks at the broken glass pieces and points at Gumball] He did it.
Jealousy: [Nervous] Ah hah, uh, see ya later! [Changes back to Gumball]
Gumball: Huh, what? what's goin' on? [Puts the trophy down]
Leslie: Uh, what's going on, is that we're about to open your locker and find a crowbar.
Gumball: [Confused] Okay.
Jealousy: [Whispers to Gumball] Dude, I wouldn't do that if I were you.
Gumball: Why, what did you make me do now? [Opens his locker and several items, including herbicides and vandalized pictures of Leslie, fall out; Gumball is shocked] What's all this?
Jealousy: Um... Plan B? [Gumball hits his face]
Gumball: [Chuckling worriedly] Well, at least there's no crowbar. [The crowbar falls out as well and Gumball is shocked again]
Nigel Brown: Wow.
Carrie: I know, right.
[In Principal Brown's office, Penny stands between Leslie and Gumball]
Penny: Gumball, I think you owe Leslie an apology.
Gumball: I would apologize but.... he'll beat me up again.
Leslie: See, he hates me, it's been like this all day!
Gumball: Look, I don't hate you, it's just... I'll explain everything when I get out of prison.
Nigel Brown: Prison? [Chuckles] Gumball, we're not the police.
Gumball: Wait, you mean I'm not wearing handcuffs?
Nigel Brown: Of course not.
Jealousy: Well, then, good luck finding me in Mexico! [Starts slamming himself into Principal Brown's door continuously until he faints; the door finally opens]
Penny: Gumball, please make an effort with Leslie.
Gumball: Yeah, okay.
[Scene changes to the park, where Gumball and Leslie are walking together]
Gumball: [Sighing happily] I'm pleased we've got to spend this time together.
Leslie: Me, too, Penny was right, we do have a lot in common.
Gumball: Phew, it's hot. Oh, a bench in the shade. [Chuckling][Pats the other side of the bench, showing where Leslie should sit]
Leslie: [Both sighing happily; both Leslie and Gumball chuckle] You know, after today, I never thought you and me would become friends.
Gumball: Well, I guess sometimes life is just full of...
Jealousy: SURPRISE! [Pulls a rope, then many slugs, snails and worms start falling from the tree onto Leslie; Leslie screams and freaks out] Ah... I see you've met my hungry little friends.
Leslie: [Tries to move, but cannot] I can't move!
Jealousy: That's right, I glued you to the bench. [Laughs evilly] I guess we won't be... "insecting" you at school tomorrow. [Laughs evilly] Wait wait, I-I can do better. [Taking a deep breath] We'll see how pretty you'll look after this, larva boy! [Laughing still] No, still not good enough. [Taking another deep breath] That'll teach you for being a creep...y...crawl- ah... you get the point. [Walks away]
[Scene changes to the school cafeteria as the school bell rings. Penny is eating with Gumball and Darwin]
Penny: I'm so pleased you and Leslie are finally getting along.
Darwin: Yeah, because for a while there, you completely lost it.
Penny: Where is he by the way?
Gumball: Uh... he had to take care of something that was...
Jealousy: BUGGING HIM!
Gumball: Nailed it! [A door is heard being slammed open. Leslie comes in, partially eaten and injured]
Leslie: PENNY, keep away from him! He's insane!
Jealousy: How did you get away? I glued you to the bench!
Leslie: You glued my pot to the bench! [The camera shows Leslie, not wearing his pot]
Penny: Oh, Leslie. Are you okay?
Jealousy: [Yells] STAY AWAY FROM HER! AHHHHHHHHH! [Runs to Leslie and starts plucking his petals]
Jealousy: She loves me! She loves you not! She loves me! She loves you not!
Penny: [Terrified] DARWIN, HELP!
Darwin: Dude, chill out! [He and Penny restrain Jealousy] We need to do something! I don't even recognize him anymore!
Carrie: I think I know what to do. [Flips her hair]
[Carrie is lighting a circle of candles on the floor]
Carrie: Don't break the circle of pepper. It's our only protection.
Penny: From what?
Carrie: Jealousy. It's taken possession of his body. And it must be EXPELLED! [Jealousy tries to escape the circle of pepper, pouncing at Carrie, but a green shield keeps him contained] Gumball, if you're there, give us a sign. [Gumball shows up in the mirror's reflection; he fogs up the mirror and writes]
Darwin: [Reads] "Writing... in this way... is difficlut." Yeah, that's Gumball, alright.
Carrie: Good, it's not too late. Now, we must present the root of his jealousy. Leslie, [Jealousy growls at Leslie] take a step forward.
Leslie: I... feel like I'm close enough already, how about you guys take a step back?