The episode begins with Gumball walking through the hallways of Elmore Junior High. However, things start to get odd as his classmates charge at him and act excitedly in his presence, calling him "LaserHeart." Terrified, he sprints down the school corridor (all while his peers chant along) and runs into Darwin and Sarah, frantically asking them who LaserHeart is. Sarah reveals that he is LaserHeart: she had been drawing him as the titular character of her comic book as a superhero with special powers coming from his optimistic heart, with each story drawn from events in his life (though not without creative freedom). Not only is Gumball excited at the realization - he decides to embrace and become LaserHeart. He then throws together a costume at home and leaves with haste to make a name for himself.
Gumball then proceeds to deliver justice around Elmore, teaching Harold to recycle and antagonizing Billy for allegedly stealing a ball (which he did not actually do). Shortly after, Darwin gets in an argument with Gumball about his idiocy but hushes at the realization that Sarah drew him into the cartoon as well as LaserHeart's sidekick, "The Smooch." He immediately joins Gumball in his adventures.
Late at night, Gumball, Darwin, and Sarah are strolling through the park when suddenly a shadow criminal mugs them. Realizing how foolish he has been acting, Gumball, defeated, takes off his costume and walks home. As Gumball and Darwin sit on their front porch talking about the incident, Sarah arrives with a new cartoon for them to read, which Gumball decides to reluctantly read.
The cartoon repaints the scene of the crime. The criminal has become LaserHeart's villain, Onyx, who proceeds to steal his optimistic heart. The two get in a fight, but right as Onyx is about to fall to his death from atop a skyscraper, LaserHeart saves his life, though it was all in vain - Onyx crushes the stolen heart. In the nick of time, The Smooch revives his optimism and the two defeat their foe, ending the story.
Gumball thanks Sarah for the cartoon, and the three watch as Nicole defeats the criminal (who had been trying to break into their car), ending the episode.
[The episode starts at Elmore Junior High. Gumball is walking in the school hallway. Colin and Felix come around the corner and start screaming at the sight of Gumball. Gumball screams in return, looking around him in confusion as to why he should be screaming]
[Colin and Felix continue screaming as they rush to Gumball and rip some of his sweater apart]
Felix: [Normally, to Colin] See, I told you it wasn't his costume; it's part of his molecular structure, as shown in Issue twenty-seven.
[Colin and Felix walk away and put down the sweater pieces]
Gumball: What the whatting WHAT?
Molly: [Off-screen] Save me!
[The camera cuts to the bottom of the stairs; Molly is at the top]
Molly: Like you saved the president in Issue nineteen!
[Molly jumps down the stairs, landing on Gumball; he splats into the nearby wall]
Molly: Of course! [Gets up][whispering] If you did save me, you would reveal your true identity. Your secret's safe with me, LaserHeart.
[Molly kisses Gumball's cheek and runs off. Gumball's face, now become a goopy substance, falls off of the locker and onto the floor in surprise]
[Cut to later. Gumball is walking through the hallway, glancing around for anyone]
Banana Joe: Hey Gumball! What a plaser to see you! [chuckles]
Banana Joe: I'd love to laser around chatting, but I have to get to h-art class. [giggles]
Gumball: [Shakes head and shrugs]
Banana Joe: See you, laser![whispering] Heart. [giggles]
[Gumball starts walking away from him, giving him a questioning look. Tobias walks by]
Tobias: [singing]Dun dun. Da-dun dun.
[Gumball starts jogging]
Leslie, Carmen, and Masami: Dun dun. Da-dun dun. Dun dun. Da-dun dun.
[Gumball starts running, and later, screaming]
Colin, Alan, Octopus, Juke, Pink Kid, Moonchild Corneille, Mister Small, Teri, Jared, Clayton, Carrie, Clare, Bobert, Anton, and Nigel Brown: Dun da-daaaa da-da-da-da daaaa daaaaaaa daaaa dun da-daaaa da-da-da-da daaaaa!
Idaho: [deep voice]Ba-ba-ba-bum.
Who is LaserHeart?
[Gumball rushes around a corner where Darwin and Sarah are standing. He looks back, panicked]
Gumball: [Panting, exhausted] Dude, [clutches Darwin's face] Who the derp is LaserHeart?
Sarah: [showing the LaserHeart issue in her hands] You are! You're a superhero, whose special power is your optimistic heart!
Darwin: You inflict justice and bad dialogue on the villains of Elmore, you're anatomically incorrect, and this is your costume.
[Darwin takes an issue from Sarah and holds it up. Its cover displays an adult, humanoid hero flying and looking over a city. The hero hardly looks like Gumball, merely having thin blue fur and very small cat ears. He is dressed in a Batman-like costume, the color scheme consisting of pink and purple, with a very midriff-bearing top that has a glowing, pink heart on it]
Gumball: [looking at the cover] But that's.. that's-
Gumball: That's... AWESOME! [takes the issue to look at it further, walking nearer towards Sarah]
Sarah: I know right! I made it myself!
Sarah: I learned from this book! [reading cover]How to Draw Superheroes.
[Sarah holds up How to Draw Superheroes. The cover shows Chuck Klein at his desk, drawing a superhero comic]
Sarah: [Turns page; reading] Draw muscles, [turns page again] then more muscles!
Gumball: [Gasps][flicking through issue pages] It's like looking in a mirror!
Sarah: And all the stories are based on your life!
Darwin: Yeah, like the time you saved the school from that plague of giant insects.
[Flashback to Gumball nervously swiping the air towards a bee as Darwin watches. As the bee flies towards Gumball, he flinches and screams. After it makes its way out of the nearby window, Gumball slams it shut. End of flashback]
Darwin: Or that time you saved the ice caps from melting.
[Flashback to Gumball disposing a soda can by throwing it into a recycling bin at Elmore Shopping. End of flashback]
Darwin: Or when you traveled through time.
[Gumball is about to flashback, but is interrupted by Darwin]
Darwin: No need to flashback, you were just sitting in front of a ticking clock.
Gumball: Nah, I remember all that, in Sarah's version it's pretty much how it went down.
Darwin: [Firmly] Gumball, [takes the comic issue to glance at it] really?
[Superhero-movie like music starts playing]
Gumball: Darwin, you can be anyone you want in this world. All you need is [strikes a pose] the power of OPTIMISM! [echo]
[Sarah smiles excitedly]
Hero To Superhero
[Cut to later, at the Wattersons'; Gumball and Darwin's room. Gumball is looking in a mirror, wearing a crude LaserHeart costume consisting of a torn tank top, Gumball's underpants, rubber gloves, pink thigh boots, a purple ski mask, and a purple cape]
Gumball: Weird, it looks super heroic in the comic, but in reality it looks more like super naked.
Darwin: It's still not as weird as Sarah cosplaying as herself.
[The camera zooms out to show Sarah also wearing a make-do costume simulating her own head, body and legs]
Sarah: [Sighs] This costume is too hot.
[Sara takes off her costume head; the real one is stuck inside. She shakes it out, letting it fall onto her body, a disfigured mess. She looks at the costume one and tosses it away]
Sarah: And anyway, it looks nothing like me. [Shakes her head back to normal] But your costume is perfecto! [Starts rubbing her knees in excitement]
Darwin: [covering his mouth; to Gumball] That girl's got issues.
Sarah: You're right! I've got every issue! [Holds up multiple LaserHeart comics]
Darwin: [Sighs impatiently] This is super pathetic.
Gumball: [Gasps][Condescendingly] In spite of my super-hearing, all I'm picking up is: [baby noises]
Darwin: [Sighs angrily] You're no superhero.
Gumball: You're right. At the moment, I'm just a regular hero, but all that, is about to change!
[Gumball looks upwards. Darwin and Sarah glance upwards as well, and as they glance back down the second time, they realize Gumball has disappeared]
Sarah: He's gone!
Darwin: [Seeing a piece of Gumball's costume wiggling through the door] More or less.
Helping Out a Fellow Neighbor
[Outside the Wilsons' house, Gumball, still in his cosplay, is glaring at someone and throws back his cape]
Gumball: [Low voice] Not so fast, punk.
Harold: [Turning back, lifting a trash can lid with a garbage bag in the other hand] What?
[The camera zooms out. Gumball is several meters away from Harold]
Gumball: [Low voice] I said, not so fast- [coughs] - [normally] Hang on, it's really hard to project in that voice.
[Gumball starts to climb Harold's car, straining to get a good grip as Harold watches questioningly. When Gumball manages to get on the roof, striking a pose as doing so, he slowly and awkwardly slides onto the back hood]
Harold: [Resignedly] What do you want?
Gumball: [Low voice; accusingly] Do you have any idea how easy it is to choke a swan?
Harold: Uh... [Hesitantly pretends to choke a swan] Pretty easy, I guess, why?
Gumball: Because one tiny piece of plastic from your trash can end up in a lake and get lodged in a swan's beautiful throat.
Harold: I wasn't gonna throw it in the lake, I was gonna throw it in the trash can.
[Gumball gets off Harold's car and puts his arm around Harold]
Gumball: Have you ever considered how beautiful this world is, and what untold damage your trash could do?
Harold: No, not recently.
Gumball: Then let me show you. Come, take my arm.
[Gumball and Harold trot along the sidewalk as wondrous music plays. Gumball is pretending to be flying with Harold, with Harold believing it as he covers his eyes, then gazes around in wonder]
Harold: Thank you, LaserHeart. Can you take me home now?
[Gumball leads him back to the front of his house]
Harold: [Annoyed] Wait, I am home, and you can't fly.
Gumball: [Normal voice] Yeah, but that still doesn't mean you shouldn't recycle.
[Gumball grabs the trash bag and chucks it across the road, aiming for the recycling bin. Instead, the bag lands on the windshield of Gary's car, speeding by. Gary screams as he swerves into a power line pole, which sparks and falls, setting fire to every other power line, and soon enough, an entire mountain, frightening three horses in the distance]
[Harold opens his mouth to say something, but when he looks around, he notices Gumball has disappeared. He shrugs at the camera]
Bringing Justice Upon the Park
[Cut to Elmore Park]
Suzy: [Crying] Where's my ball?!
Billy: [Firmly] Suzy, I've told you, I know not its whereabouts.
Gumball: [In the tree; Low, growly voice] Come over here.
[Suzy stops weeping as she and Billy walk closer to the tree]
Gumball: Like, two more feet.
[The two children move even closer to the tree]
Gumball: N-no, wait, back up a bit.
[The children step back slightly]
Gumball: Alright, cool.
[Gumball lands heroically and grabs Billy. Suzy runs away and shrieks]
Gumball: [Scary voice] WHERE IS THE BALL?!
Billy: I don't know!
Gumball: WHERE IS THE BALL?!
Billy: [Frightened] Suzy lost it, I swear!
Gumball: SWEAR TO ME!
Billy: I just did! [Starts weeping]
Suzy: [Off screen; joyfully] I found it!
Gumball: [Putting Billy down] Oh my gosh, I'm so sorry. [Pats Billy's head] Please stop crying.
[Billy continues to sob as Gumball looks around anxiously]
Gumball: Hey, hey, uh- let's play Monkey in The Middle! I'll be the monkey!
[Once Gumball grabs him again, Billy stops crying]
Gumball: [Scary voice] PLAY WITH ME!
[Cut to Gumball, Suzy, and Billy merrily playing Monkey in The Middle as Darwin and Sarah watch from a bench. Sarah glances from the game to the sketchbook in her hands as she draws. Billy tosses the ball at Gumball's face, pulling down his ski mask over his eyes and mouth. Billy tosses it at Gumball's face for a second time]
[The camera zooms in on Darwin and Sarah. Darwin looks at what Sarah is doing. The camera then shows the cover issue Sarah is drawing, which displays LaserHeart pushing back a meteor from crushing two frightened citizens]
Darwin: What? Stopping an asteroid? He can't even catch a ball!
Gumball: [Normal voice; brushing himself] Hey, this collar takes away my peripheral vision, okay? What is wrong with you, anyway? [Deep voice] You're more of a downer than a depressed parachute, buster!
Darwin: Now you're even making bad comic book jokes.
Gumball: [Normal voice] So what?
Darwin: So, superheroes are lame; they wear their underpants on the outside, they have stupid names like "Manatee Man", and have pointless powers like a super tongue or an elastic butt. The only people into them are fedora-wearing neckbeards and I want nothing to do with it.
Sarah: I should probably take you out of the comic, then.
Darwin: Wait, what?! [Happily]I'm in it?
Sarah: Yeah! You're The Smooch, LaserHeart's sidekick.
[Sarah shows Darwin the cover of Issue 37 of LaserHeart that displays The Smooch running through the streets at night]
Sarah: You kiss people to make them feel better.
[All of a sudden, Darwin, dressed in a cosplay of The Smooch, lands near the bench from somewhere above]
Darwin: [Heroic voice] Holy pamper cream, LaserHeart. Enough bickering, we've got stuff to do. [Throws back cape]
[Sarah squeals in excitement]
Taking Action and Producing More Comic Issues
[The screen twists in a superhero-esque manner, with accompanying action music. Cut to a neighborhood, a cat is stuck on a tree branch. Gumball and Darwin try to get to it by climbing, however, as they inch closer to the cat, it gets closer to the end of the branch, and as the cat jumps onto the nearby car to safety, the branch whips back, catapulting Gumball and Darwin. The camera shows Issue 62 of LaserHeart, where LaserHeart and The Smooch save a tiger kitten from an erupting volcano]
[Cut to a dentist's office, where Sarah's teeth are about to be drilled as Gumball and Darwin read magazines in the waiting corner. The camera shows Issue 41 of LaserHeart, where LaserHeart and The Smooch break into a building where Sarah's damsel-in-distress counterpart is tied up and threatened to be amputated by a large, whirring saw]
[Cut to a backyard, at night. Gumball scribbles a heart symbol onto the lens of a flashlight with a pen and shines it onto a wall to see the effect. Instead of showing the entire heart symbol, half of the light shines onto something else, displaying only the top part of the heart. A person whose head resembles Richard's butt notices the signal, and, thinking it's his symbol being flashed, tears off his regular clothes to reveal his red-and-yellow schemed superhero costume. When he arrives where Gumball and Darwin are standing, Gumball adjusts the flashlight to shine the entire shadow on the wall. The person walks away disappointed, making a sad fart. The camera shows Issue 45 of LaserHeart, where someone is shining a LaserHeart signal into the sky]
[Scene changes to Gumball, Darwin, and Sarah walking in the park at night]
Sarah: [frightened] Are you sure we should be at the park at night?
Gumball: [deep voice] Fear not, young lady. LaserHeart can strike down any foe! He's here to force the light of justice where the sun doesn't shine. [normal voice] That came out a bit wrong.
[A strange figure appears in front of them]
Strange figure: Give me my wallet.
Gumball: [scared] Uh, sure, where is it?
Strange figure: In your pocket!
[They all get scared and Darwin starts smooching but Gumball covers his mouth]
Sarah: LaserHeart, do something!
[Gumball gives the strange figure his wallet. The person takes the money out and runs away. Sarah starts to run away]
[Gumball's eye start to well up and he takes off his costume walking away dumping it in the garbage. They appear on the steps of their house sitting down]
Darwin: Should we call the police?
Gumball: Tell them what? That we were dressed up as eastern European pop-stars and got mugged for seven dollars by a shadow?
[They both look down sadly. Sarah pulls up the comic in front of them and smiles]
Gumball: Sarah please, just stop.
Sarah: Just read it.
[Gumball sighs and opens the comic]
Reading the comic
Gumball: [Reads from comic] I'm so glad you guys are still friends despite fighting for my affections?
[Gumball and Darwin look at her]
Sarah: What? It's fanfiction, there's got to be a better shipping.
[Gumball turns the page]
Sarah: Aah, what a pleasant evening in the park.
[The shadow figure suddenly appears, giving a roar]
Gumball: Onyx! I should've known.
Darwin: Don't worry LaserHeart, I got this!
[The Smooch attempts to charge Onyx, but ends up getting beaten up]
[Onyx tries to take away LaserHeart's optimistic heart while laughing]
Gumball: It was a trick!?
Onyx: Yes. I only pretended to attack your beautiful fiance to get your most important weapon.
[Scene goes back to reality]
Darwin: [Confused] His bizarre over-developed nipple-less pecks?
[Scene changes to the comic]
Onyx: Your optimistic heart! [Rips heart from costume] Without its light, my shadow can take over the world, and there is nothing you can do without your superpower!
Gumball: Wrong. [Gets up] I'm still totally stacked!
Onyx: I cannot compete with your mighty bulk, but I can run!
[Onyx runs away with LaserHeart chasing him. Then, LaserHeart is in the city, trying to catch Onyx while making slightly odd body shapes. The scene returns to reality]
Gumball: Yeah I don't think a body can make those shapes. Onyx took his heart, not his spine.
Sarah: Just keep reading.
[Scene zooms back into the comic. LaserHeart lands on a building while Onyx is hiding]
Onyx: [Laughing] The fool will never find me. I shall hide in the shadows-
[Onyx gets interrupted when LaserHeart lifts up the wall he was hiding in]
Gumball: I hope I'm not... Onyx-spected!
[Scene goes back into reality]
Gumball: Oh, come on. [Continues reading]
Onyx: Without your laser heart, you cannot defeat me!
[Onyx punches LaserHeart, then LaserHeart punches him back. This is looped over and over for a bit. The scene goes back to the trio with Gumball staring at her with contempt]
Sarah: Yeah, the issue was running short, so I photocopied those frames to pan out the fight scene.
[Onyx and LaserHeart punch each other a bit more. Then, LaserHeart is about to punch Onyx, but stops. Onyx is confused, but then gets blown by the punch, sending him off the skyscraper. However, LaserHeart grabs Onyx]
Onyx: Why would you save me!?
Gumball: Because I have hope... Hope that someone as dark as you can see the light.
Onyx: Well, you were WRONG! [Smashes the heart into pieces]
[Gumball loses his strength, but uses all of it to lift Onyx back up onto the building. Gumball is weak, while Onyx is laughing. Darwin screams]
Darwin: Sorry. I got caught up in the drama. Please continue.
Onyx: Where is your hope now, LaserHeart?
Darwin: Right here! [Makes a smooching sound. Jumps over to LaserHeart and kisses him on the cheek]
[Due to this, LaserHeart's powers return]
Gumball: My powers have returned.
Onyx: [Shocked] How? I crushed your heart!
Gumball: Fool, anything is possible with... THE POWER OF OPTIMISM!
[LaserHeart's heart shoots out a laser at Onyx, destroying him]
[LaserHeart lands softly]
Gumball: I guess he should've put on some sunscreen.
[The comic ends]
What Goes Around Comes Around
Gumball: [Sigh of relief] Thanks, Sarah. You really taught me something today.
Darwin: That even in this darkest hour, a true hero always has hope.
Gumball: Yeah, but more importantly, what goes around, comes around.
[The strange figure is seen trying to break into Richard's car with Nicole behind him. Nicole taps his shoulder, and punches him, ending the episode]