Connor and Amaya are contacting each other through their walkie-talkies and are trying to contact Greg. Meanwhile, Greg is in his room trying to find his walkie-talkie with a lot of his stuff scattered about. After a few moments, Lionel comes out of his backpack with his walkie-talkie in his mouth. Greg thanks him, grabs his walkie-talkie, and returns Connor's call. Connor asks what Greg is doing, to which Greg explains that he is cleaning his room. The reason why is that he would not be allowed to leave the house to watch the carnival parade unless he tidies it up. Connor comments how the parade is going to be amazing, and how Greg must be really excited for the lizard float since it is going to be a part of it. Greg agrees with him, saying that it is his favorite float. After Greg's comment, Connor tells him to continue cleaning his room while he and Amaya go to HQ tonight just in case there are any nighttime villains coming to mess up the parade. Greg decides to come with them as well, although this concerns both Connor and Amaya because of his messy room. Greg, though, just convinces them that he will do it later and has to find his camera, which he probably thinks is in headquarters since he cannot find it in his room. Connor and Amaya agree to this, and the three pronounce their signature phrase.
Upon arrival at headquarters and into Gekko's room, the PJ Masks see that the room is also messy. Catboy comments to Gekko how it is just as messy in Gekko's base room compared to his room in his house, and says that he was supposed to clean the room before, to which Gekko responds that he was going to do that, but later. Soon, Owlette finds Romeo's Sniff-O-Whiff and the Small-Sizer, and comments to Gekko that he was supposed to put them away in a safe place. Gekko starts thinking of something to say in response, but Catboy just shakes this off, and tells him that he and Owlette will go up into Catboy's base room to track any signs of nighttime villains in the parade grounds while he cleans. As they leave, Owlette also warns Gekko not to mess around with Romeo's inventions. Gekko agrees to this, and starts cleaning. As he begins to pick up his things, Gekko notices the Small-Sizer and decides to clean up his room with it, thinking that it is not really playing with the invention itself. While imitating Romeo on his slide, Gekko shoots all of his stuff with the gadget, making it small and making it look like his room is clean. After he jumps off his slide and starts walking, he notices another button on Romeo's invention and presses it to see what it does. Just then, he accidently steps on the shrunken cactus plant and falls down, accidently firing the gadget in the process. The beam zaps out, and after a few reflections off a couple of objects, it hits Gekko as he braces for impacts. When Gekko opens his eyes, he starts to stand up, only to hit his head on the ceiling. He soon realizes that he turned the Small-Sizer into a Super-Sizer, and gets excited now that he is big.
Gekko goes up into Catboy's base room and greets Catboy and Owlette, who are still tracking any nighttime villains down in the parade grounds. When they both turn around to look at Gekko, they start screaming and ask Gekko what happened. Gekko explains to them that he accidently zapped himself with the Small-Sizer in reverse, resulting in him growing bigger. Catboy states that they will zap him back to his normal size. However, Gekko refuses to go back to normal, saying that it is great to be "Giant Gekko," and proclaims that with his size, he will be able to stop anyone who is ruining the parade. In response to his comment, Catboy and Owlette exchange worried glances at each other, until the PJ Picture Player tracks Luna Girl and her moths at the parade grounds. Catboy and Owlette take the Cat-Car to get there, while Gekko jumps out of HQ and runs along, following them.
Switching to the parade grounds via Gekko's Gekko symbol, Luna Girl proclaims that the parade is hers, as she is going to steal the floats and be crowned the parade queen. Meanwhile, as Catboy and Owlette are driving through the town, Gekko runs up to them and grabs the Cat-Car, startling them. Gekko proclaims that he will get the two to the parade grounds instantly and throws the vehicle there. As Catboy and Owlette start screaming, Luna Girl and her moths, who are busy cheering for Luna Girl, notice the Cat-Car coming in for a landing. After a few bounces, the Cat-Car screeches to a stop; Catboy and Owlette dizzily get out of the vehicle and collapse to the ground. Luna Girl comments on their entrance, until she hears a roaring sound from Gekko, who has jumped to the parade grounds. Upon landing, Gekko introduces himself to Luna Girl as "Giant Gekko" and proclaims to stop her from stealing the floats, especially his favorite float. Luna Girl denies this, though, and plans to take the stolen floats down into the main part of the town and wake everyone up with her own parade. She then commands her moths to capture Gekko. As the moths do that, though, Gekko just frightens them off and walks away. Annoyed at this, Luna Girl grabs a float with her Luna Magnet and commands her moths to do the same and follow her to the town. The moths proceed to do it; however, they are not able to lift them off the ground.
As Luna Girl scolds them for not being able to pick up the floats, Catboy starts explaining his plan on how to stop Luna Girl and her moths. Gekko, though, also has an idea, and takes out the Super-Sizer. He explains that if he super-sizes the garbage bin, then it will be big enough to trap Luna Girl and her moths. With that, he begins to activate it, only for it to instead fire at one of the moths and not the bin. The moth soon grows bigger, much to the PJ Masks' dismay and to Luna Girl's delight. Owlette tells Gekko to quickly shrink it, but Gekko says he will do it later since he still has to super-size the bin. Unfortunately for him, it fires towards the inside the bin, and the cans inside grow. They pop out of there from their size, and then land over the PJ Masks. Meanwhile, Luna Girl sees what is happening and gets an idea. Using the large moth instead of her Luna Board, she quickly flies over to Gekko and takes the Super-Sizer from him. Now with the Super-Sizer in her hands, she can zap the moths into a bigger size, enabling them to take the floats into the city. As she begins to do that, she turns the Super-Sizer back into the Small-Sizer and zaps Gekko, returning him to normal size.
As the PJ Masks wonder what to do now, Gekko declares to get the Super-Sizer back from Luna Girl and turn him back to his big size. Catboy pushes this off, though, declaring instead to fix Gekko's moth mess, and tells Owlette to have the moths chase her while they retrieve the Super-Sizer from Luna Girl. After that, Gekko will be able to shrink them back down as Owlette proceeds to fly past him. Owlette complies, and calls the moths to chase her as they start picking up the floats. Then, with Super Cat Speed, Catboy runs around Luna Girl to make her dizzy, giving Gekko a chance to sneak up on her using Super Gekko Camouflage and grab the machine from her, disappearing afterwards. As Luna Girl tries to figure out where Gekko is, the boys quickly hide behind one of the cans. As Catboy leaves to check what Luna Girl is doing, he reminds Gekko of what he is doing. Gekko gets ready to fire the invention, until he notices a pigeon flying over him. He soon gets an idea of how to improve Catboy's plan, and fires the pigeon with the machine. Hearing the sound, Catboy stops where he is and turns around to see Gekko on the big pigeon, much to his annoyance. To make things worse, the pigeon starts running around. Meanwhile, Owlette is still being chased by the moths, until she sees the chaos unfold. After Gekko is thrown off the pigeon, she stops to save Gekko, while the moths proceed towards Luna Girl. After the PJ Masks regroup, Luna Girl proclaims victory over the PJ Masks, and with her moths, she takes the floats to the main part of town.
The PJ Masks now realize that the only way to stop Luna Girl from waking everyone up and seeing her in the town is by shrinking the moths. However, Gekko reveals that he lost the Super-Sizer again when he fell off the pigeon. To make things more complicated, after spotting it out, the pigeon takes it away from the team. Not knowing what to do now, Gekko realizes his fault and apologizes for not being able to clean up his messes earlier. Suddenly, he gets an idea and runs towards the pigeon, imitating a bird. Owlette warns him not to get it excited, but Gekko points out that this is what he is exactly going to do. Soon enough, Gekko leads the bird away from the machine, and Owlette quickly grabs it. As they both praise Gekko, Catboy and Owlette proceed into town to catch up with Luna Girl and her moths. Meanwhile, Gekko is still leading the pigeon away, until he comes to the pile of cans and starts realizing of cleaning up this mess earlier as well. The pigeon then hits a can into the air, and Gekko catches it using his Super Gekko Muscles. As he throws it to the side, he sees the pigeon chase after it and give it back to him, as it thinks it is a game. Gekko pets the bird, until he notices what is happening around the town. Seeing how Catboy and Owlette need his help, because of what just happened, Gekko thinks up an idea.
Transitioning to the town via Gekko's Gekko symbol, Catboy and Owlette are finishing up shrinking the moths. As Owlette is busy being chased by the moths, she flies past Catboy, who then proceeds to fire the machine at them to shrink them down. After shrinking the moth that Luna Girl is on, the moths are all back to normal size, just as Gekko regroups with the PJ Masks. Angered by this, Luna Girl grabs the lizard float and calls her Luna Board to come to her. As it comes, a couple of the large cans are tied to the back of it. This does not faze Luna Girl, though, until she sees the pigeon running towards her. She starts to fly away, but to no avail since the cans are weighing her down. With no choice, she lets go of the lizard float and grabs the cans instead so she can easily fly away, leaving Gekko to catch the lizard float with his Super Gekko Muscles. Once that is finished, Gekko whistles for the bird to come back. As Owlette pets the bird, Gekko grabs the gadget from Catboy and shrinks it back down to its normal size. After petting it, it soon flies away. Gekko then declares to clean up the rest of the messes, all while not using the invention anymore, and the PJ Masks cheer their victory phrase.
The next day, Greg is cleaning up his room. As he finishes putting away the last of his things, Connor and Amaya enter in, and are amazed by its neatness. Greg points out that "it took forever," but since his room is now clean, he is now able to go to the parade. Suddenly, his closet starts to rumble. As Lionel tries to keep it closed, Greg yells at the others to get down. Soon, the closet barges open, and most of Greg's stuff falls out. Greg then points out his camera as Lionel pops out with it, and the three start laughing, ending the episode.