The episode begins with Connor, Amaya, and Greg heading towards the playground. Upon their arrival, Greg points out the Armadylan signal drawn in the sandbox. With it is a note from Armadylan saying that he got their “message” and that he will meet them “there”. At night, after the PJ Masks transform and head to HQ, PJ Robot shows them through the PJ Picture Player that Armadylan is entering through the Mystery Mountain portal.
The team takes off in their PJ Rovers and head to Mystery Mountain. Once they reach the foot of the mountain, Owlette uses her Owl Eyes to spot Armadylan climbing up the summit. Knowing that An Yu doesn’t like people showing up unexpectedly, the group runs up before anything could happen.
Meanwhile, An Yu, who is taking care of one of her plants, gets a warning signal from her staff of an intruder. She flies down and stops a rolling Armadylan halfway up the mountain. She asks him what is he doing here, to which he responds that he is helping his friends defeat a dragon person. Immediately, he realizes that An Yu is the person he described, and assumes that she is the villain of the mountain. He attempts to stop her, but An Yu swiftly and expertly dodges his every move, until he uses his Thunder Thump. An Yu is knocked down, and Armadylan continues climbing, grabbing her staff that she dropped during their confrontation.
Back in the bamboo forest, Night Ninja appears with Teeny Weeny. Using one of the scrolls from the museum, the two teleport to the summit and get into position. Armadylan arrives, and when he steps on a trap, the dragon statues fire Sticky Splats at him, pinning him to the ground. He drops the staff, and Night Night obtains it. He reveals that he was the one who sent the note, much to Armadylan’s dismay and embarrassment. He tricked him into thinking that An Yu is a villain so he can stop her and grab her staff since she is powerless without it. Now that he has it, he is going to send her back into the Dragon Gong forever so she will never interfere with him.
Night Ninja hits the staff against the Dragon Gong to transform it into the Dragon Mallet. An Yu quickly arrives, but stops in her tracks when she sees Night Ninja with the transformed staff and realizes what he is going to do. Hearing this conversation, Teeny Weeny tries to stop the villain from doing so, but he hits the gong, and An Yu is sent back. Night Ninja then makes his way into the pagoda to unlock its secrets, and Teeny Weeny reluctantly follows him.
The PJ Masks soon arrive and find Armadylan. He tells them about Night Ninja, that he tricked him into getting An Yu’s staff so she can be trapped in the gong again, enabling him to go inside the pagoda and unlock its secrets. Gekko helps Armadylan out of the Sticky Splats, and expressing his desire to help, the group makes their way to the pagoda to retrieve the staff. Inside, Teeny Weeny sets the scrolls up in a circle near the cabinets where the secrets are locked. He overhears the PJ Masks coming, but Night Ninja is not fazed by this, knowing he will easily stop them, just like he did with Armadylan and An Yu.
Night Ninja asks Teeny Weeny to give him the invincibility scroll. However, after feeling remorse of the recent events that took place, Teeny Weeny refuses, much to the villain’s surprise. He grabs one of the scrolls and the Dragon Mallet and leads Night Ninja on a chase. He arrives at the Golden Dragon Statue, and proclaiming that “it’s time to be a hero,” he chants the spell written just as Night Ninja grabs him, kicks the mallet away, and the two disappear, just as the heroes run inside.
Astounded, the group picks up the museum’s scrolls scattered on the floor and the Dragon Mallet. They run back outside, hit the Dragon Gong two times, and An Yu is set free again. She wonders where Night Ninja and Teeny Weeny went, but when the PJ Masks tell her about their sudden disappearance, she understands that Teeny Weeny used the Vanishing Scroll to transport him and the villain out of the mountain and back into town. The PJ Masks then introduce Armadylan to An Yu, and explain to her that Night Ninja tricked him into thinking that they needed his help to capture her, thinking that she was a villain. Armadylan apologizes to An Yu for assuming her as a villain and stealing her staff and promises to never let it happen again.
An Yu cautiously forgives Armadylan, but denies to become friends with him. He tells her, though, that he is not so bad once she gets to know him, and that it could be possible to become friends. The PJ Masks confirm this with a laugh, and Armadylan holds out his hand towards her. An Yu doesn’t make a move at first, but after a few seconds, she warms up to him, and she shakes his hand, confirming their friendship. To celebrate, the heroes cry out the PJ Masks’ signature victory phrase, and the episode ends.
Don't get tricked.
You should stand up for yourself no matter what anyone says.
You have to be careful of who you trust.
This is the fourth time Night Ninja doesn't appear with his Ninjalinos (other than Teeny Weeny).