The episode begins with the Lunar Fortress firing laser beams while Luna Girl tries to fight back with her Luna Magnet. She retreats with Motsuki as it gets zapped, and she reluctantly agrees to message the PJ Masks for help through Motsuki’s insistence.
Meanwhile on Earth, Connor is playing a game on his tablet called “Whiskers and Wormholes”, which features a cat space explorer. He mentions to Amaya and Greg that he has learned a lot about space through the game, despite the fact that the trio has gone to the moon numerous times, and hopes to make some new cat explorer discoveries. He soon gets his chance when they receive Luna Girl and Motsuki’s message contacting them about the Lunar Fortress.
That night, the PJ Masks arrive at headquarters and take off for the moon. As they travel, Catboy shares his eagerness about taking on the role of a cat explorer, much to the team’s annoyance. Luna Girl contacts the group, and when Motsuki appears behind her, the fortress zaps her, and it pulls her away. The fortress continues zapping, and she is forced to leave.
Luna Girl meets up with the PJ Masks as they land and tells them what happened. They head over to the fortress, and see that it is filled with negative space energy. Owlette suggests staying back and thinking of a plan when Luna Girl states about sticking together, but Catboy desires to get in and find out the source of the energy, confident that they will be safe under his protection.
He drives up the path, and Gekko reluctantly follows him, only to be zapped off his PJ Rover. He takes cover and calls for Luna Girl, but when she comes over, she gets zapped. Gekko tries to get her out, but gets trapped as well. As the fortress pulls them inside, it continues firing lasers, knocking Catboy off his PJ Rover.
He takes cover with Owlette, who attempts to fly after them. She advises going back to HQ and thinking of a plan, but it falls on deaf ears as Catboy decides to forge on, not wanting to think. He runs towards the entrance, and Owlette flies along to cover him. However, the fortress also zaps her, and as Catboy tries to save her, she is pulled in.
Catboy barges in the fortress to confront the source responsible for bubbling those captured, but he only sees Owlette, Gekko, and Luna Girl being pulled out of his sight. Catboy runs after them, but the fortress prevents him from going any further with Luna Girl’s crystal statue. A group of moon balls are summoned, and they attempt to zap Catboy. He quickly hides from them, and he expresses remorse that he let everyone down. Wanting to make up for his mistake, Catboy exits the fortress so he can decide how to save them, barely escaping the moon balls chasing him.
PJ Robot soon finds Catboy and indicates one of the craters glowing. While witnessing everything from the PJ Picture Player, he spotted it and checked it out for himself to see something surprising. They head inside the hole, and they see an unharmed Motsuki with a huge moon crystal glowing red. Firing a beam at Catboy, only for PJ Robot to take the hit, she reveals that she found the crystal that can be used to control the Lunar Fortress using her negative thoughts. She wanted to have the fortress all to herself, so she pretended to be captured so she can take Luna Girl and the PJ Masks prisoner.
Continuing to use her negative thoughts, Motsuki uses the crystal to prevent any attempts from Catboy to stop her. Catboy does not stand down, though, because he knew he got everyone into trouble, and expresses determination to save them. Suddenly, the crystal glows blue in response. Realizing it could pick up positive thoughts as well, Catboy uses them to rid the fortress of Motsuki’s bad energy. She tries to overpower his thoughts with her own, but she gets overpowered instead, and the fortress releases everyone.
Catboy reunites with the group with a recovered PJ Robot and the crystal. He informs them of Motsuki’s plan to take over the fortress using the crystal she found. He apologizes about forgetting what being a PJ Mask is really about, and the team forgives him and thanks him for rescuing them. Motsuki soon recovers and joins the group. After Luna Girl teasingly offers her a bedtime story about what happened, she flies away, and the villainess chases after her, leaving the PJ Masks to shout out their signature victory phrase.
A hero always helps. Heroes are kind and always listens to their friends, and are a part of a team.
The moon reveals to have another moon crystal that feeds on Motsuki's negative energy, which lets her take control of the Lunar Fortress.
This is the eleventh time the PJ Masks and Luna Girl go to the moon.
It appears that Luna Girl's powers have grown strong enough to the point where she does not need her Luna Magnet to breathe in space.