The episode begins as the PJ Masks return to HQ after a mission involving Romeo. The next day at school, Greg shares a project about being underwater. After finishing his presentation and everyone leaves the classroom, Amaya notices Romeo and Robot in one of the presentation slides, which excites him, taking into mind of what happened last night.
That evening, Gekko swims over to the cavern, where Romeo and Robot are located. They are looking for an underwater crystal hidden in one of the stalagmites that requires super strength to break it. When Gekko hears that the villain is planning to use its powers to take over the moat, he swims back to headquarters to warn the other PJ Masks. Unbeknownst to him, it turns out that Romeo was expecting this to happen as part of his plan.
Gekko tells the team about the underwater crystal that he overheard Romeo and Robot talking about. The others are wary about this, though, because they find it strange that Romeo would suddenly be interested about being underwater. Additionally, they are aware about what happened the last time Gekko found anunderwater crystal. Gekko assures them that this is to help stop Romeo, and despite a lack of reasoning behind the villain’s underwater intentions, he feels that it is the place where he can be a real hero. PJ Robot builds a scanner to help him find the crystal, and he heads back to the moat while the rest of the team watches from Gekko’s camera.
Gekko returns to the underwater cave to find that Romeo and Robot have left. He scans each rock formation, until Owlette informs him that one is glowing. Gekko uses all of his super strength to break the stalagmite, and it reveals the crystal hidden inside. He grabs it, but it starts floating away, up to the town and into the sky, where Robot grabs it.
Taking Gekko prisoner in the Sky Factory, Romeo reveals that the underwater moat crystal is actually a Sky Crystal. He needed Gekko’s powers to break open the rock so he can use its floating powers to take over the sky. To do that, he connects the crystal to the factory’s computer and shows him his Super Floaty Beam. He zaps multiple objects and structures around the town so he can create his own world in the sky.
Romeo continues to zap some more buildings as Robot takes Gekko away. Catboy and Owlette suddenly arrive in the Owl-Glider to confront the villain, but he zaps the museum in response, sending the two spinning out of control. Gekko contacts them to see if they are okay, and apologizes to them about wanting to prove to be a hero. Although it is up to him to save them and the city, he is in the sky and fears that he cannot be a hero there. However, Catboy and Owlette reassure him that it is possible: he can be a hero regardless of where he is located.
Taking these words into heart, Gekko agrees and escapes from Robot’s clutches. Romeo notices and orders Robot, joined by a couple of Fly Bots, to capture him, but Gekko leads them on a chase, using a combination of his powers. Once he outwits the robots, he then enters the Sky Factory while staying camouflaged, and with his strength, he obtains the crystal. The laser deactivates, and as Catboy and Owlette land safely, Gekko comes out and lets go the crystal. Romeo runs over to save it, but he starts floating away with it as he grabs it. Despite Gekko’s warning, though, he refuses to let go in desires of being Master of the Sky.
Nevertheless, Gekko climbs up and grabs onto Romeo, and with the Anti-Gravity Boots in his hands, he activates them to weigh them down. The two return to the ground, while the crystal escapes from Romeo’s hands and floats away, much to his anger and dismay. Catboy and Owlette commend Gekko on a job well done, stating that he truly is a hero everywhere. Gekko thanks them, and as the PJ Masks return to headquarters, they shout out their signature victory phrase when Robot starts it off, much to Romeo’s annoyance.