The episode begins at the pagoda of Mystery Mountain, where Night Ninja and his Ninjalinos are doing a ritual. Spying on them, the PJ Masks run over to intervene, when Gekko steps on a booby trap and gets flung into the air. He slides down the mountain with one of his shields into a pile of mountain splat. Knowing that Catboy and Owlette, respectively, have Super Cat Speed and Owl Eyes to dodge and see the booby traps, he decides to not take any more trips up to the top of the mountain, feeling that his Super Gekko Muscles are not good there.
Since morning is almost here, the PJ Masks decide to call it a night, knowing that the ninjas will not be able to finish anything within that time frame. However, by the next day, as they walk in the town, talking about the mountain, they see mountain splat spilled out from the Mystery Mountain portal, which has something to do with what Night Ninja is planning.
That night, the team checks the PJ Picture Player, and Night Ninja is shown performing a dance ritual at the pagoda to make the mountain splat, while the Ninjalinos are collecting bucketfuls from the geysers below. This means that the PJ Masks will have to go back to the mountain to stop the ninjas. Gekko is wary of this, but when he notices the boulders, he gets an idea.
Once the PJ Masks arrive at Mystery Mountain, Gekko tells Catboy and Owlette to head up to the pagoda while he takes care of the fountains by plugging them up with the giant rocks. Despite a bit of bad luck from last night, he feels that he is just the muscle, which is what the section of the mountain needs. Catboy and Owlette comply, and they arrive at the gates of the pagoda. Night Ninja finishes up the ritual, which is for a dancing potion. With it, he is going to add it to the mountain splat to make it flow. This will enable the Ninjalinos to collect it, and with its strength, the ninjas can use it to splat the whole city.
Catboy and Owlette grab the potion from Night Ninja and head down the mountain. They meet up with Gekko as he continues to throw the rocks at the geysers and tell him about going back into town to analyze the potion at headquarters and do some research on the dance ritual. Gekko is offered to come with them, but he declines, wanting to continue his job to ensure the mountain splat does not flow out. The team splits, but the mountain begins to rumble.
Catboy returns to HQ for PJ Robot to analyze the potion, while Owlette is at the library looking for any information about the dance. Meanwhile, Gekko continues to block off the geysers as the mountain continues rumbling. Catboy and Owlette soon return, and show him a reverse potion that PJ Robot made to harden the mountain splat. For it to work, they need to do to the dance backwards. They just have to dodge the Ninjalinos and avoid the booby traps. Gekko is still adamant to come up with them, though, because he has more fountains to cover, and he still feels he is needed down here since strength is his thing.
Catboy and Owlette reluctantly agree and head to the pagoda. They attempt to head to the hole where the source of the mountain splat is located, but the Ninjalinos prevent them from doing so and surround them while the mountain continues shaking. Night Ninja, who has a new potion, explains that although Gekko is using the boulders to plug up the mountain splat fountains, the blockage is building up pressure to cause an enormous volcanic explosion, which will cause piles of mountain splat to pour down the mountain and into the city.
Catboy and Owlette run back down to warn Gekko, who is now resting after covering up all the mountain splat geysers. As soon as they arrive, though, the mountain explodes. Mountain splat rains down everywhere, and it hits Catboy and Owlette. With them stuck, it is now up to Gekko to stop the eruption before the flow heads to the town.
Finally convinced and now determined, Gekko agrees and runs up to the pagoda. He steps on another booby trap and gets flung out, but he does not give up and runs back inside, this time using his Super Gekko Camouflage. It turns off as he trips, and Night Ninja sends his Ninjalinos to stop them. Gekko forges on, so Night Ninja attempts to send him down the hole. He is able to recover, and once the villain is hit with the mountain splat, he performs the dance ritual backwards, and pours the reverse potion in the pagoda courtyard floor. The mountain splat is hardened, and the mountain stops erupting.
The ninjas retreat as everything returns back to normal. Gekko returns to Catboy and Owlette and cuts open the splat boulders with his lizard tail using his super strength. The two commend him, and he agrees that he is more than just the muscles of the team, and he will always have Mystery Mountain as the special place to recognize his worth. With that, the PJ Masks proclaim their signature victory phrase, and the episode ends.
Use more than one skill to solve a problem.
This is the second episode with the word "Vs." in the title.