Connor is practicing for the upcoming go-kart race, but according to Amaya he’s still not fast enough. He briefly considers taking a shortcut, but Greg reminds him that would be cheating. Then Connor notices a flyer on the ground, which announces another upcoming race named the Moon Prix. Greg points out that Romeo is prominently featured on the flyer. Fearing the mad scientist is up to no good again, the three friends decide to investigate.
That night, in HQ, the PJ Masks see that Romeo, Luna Girl and Night Ninja have gathered in the woods with their respective vehicles for the race. The PJ Masks also go there in the Cat-Car, but Romeo is waiting for them and uses his shrinker to steal the Cat-Car. He intends for the car to be the price in the Moon Prix. So Catboy gets his go-kart and enters the race to win his Cat-Car back. At the last moment, the Wolfy Kids also enter the race with their kick scooters and go-kart.
The race begins, and all contestants are equally matched until the villains begin to use their weapons (Romeo’s shrinker, Night Ninja’s sticky splat, and Luna Girl’s luna magnet) to cheat. Catboy decides the only way to win now is to cheat, too, and he convinces Owlette and Gekko to help him take a shortcut. When the villains proceed to trap Catboy in a sticky splat web, he responds by having Owlette and Gekko take out the vehicles of Romeo, Night Ninja and Luna Girl. Catboy himself takes a second shortcut, and accidently causes the Wolfies to crash their vehicles.
Luna Girl and Romeo catch up with Catboy again and use their shrinker and Luna Magnet on him, but he dodges them and they hit the Wolfy Kids’s vehicles instead, merging them into a powerful racecar which Howler dubs the Wolf Wheels. While the Wolfies rejoin the race with their new car, Catboy regrets his cheating and laments how he will never win now since his own go-kart has a hole in the bottom as a result of the last crash. Owlette points out that Catboy can use this to his advantage; instead of driving his go-kart, Catboy has to push it, using his superspeed.
With their new car, the Wolfy Kids easily overtake the other villains, and Catboy follows close behind. For a moment it seems Catboy will win, but the clouds in the sky clear, allowing the Wolf Wheels to get a power boost from the now unobstructed full moon. They overtake Catboy and finish first. Catboy takes it in strides however and congratulates the Wolfies with their victory, while Romeo reluctantly gives them the trophy with the Cat-Car on it. However, the Wolfies have no interest in the shrunken Cat-Car since they have their Wolf Wheels now, so they give the car back to Catboy. Using his camouflage, Gekko climbs onto Romeo’s vehicle and uses the shrinker to unshrink the Cat-Car. Romeo and the other villains leave. Despite having lost, Catboy is convinced he can win the go-kart race with all the experience he got this night. The PJ Masks thus shout their victory cry.
Don't give into temptation and don't cheat.
This is the second time all the current villains appear (except for Mothzuki).
The first time they appeared together was in "Romeocoaster."