The episode begins with Captain Jake, Connor, Greg, and Amaya walking with bags of chocolates; milk, white, mint, and dark, and holding bouquets of pink, red, and white roses. They were walking to the Disney Junior Town Manor to decorate for the Valentine's Day Party tomorrow but when they got inside, they find that everything has been trashed! Over at the corner, Kwazii, with his magical cleaning brush that is now a broom, was helping to clean up while Sofia, James, and Amber were busy tidying up the paint that was spilled everywhere and putting half eaten chocolates into the garbage bags.
When they got to their friends, Connor asks what happened. James explains that someone has sabotaged the preparations and unless someone finds out who it was, the Valentine's Day party will be canceled.
The four friends decide that they should go into the night to find out who is ruining their plans for the party and stop him or her. That night, when the PJ Masks met at the HQ, Catboy picks the Cat Car and they hop in, then fastened their seat belts before Cat Boy drove it out into the streets. When they were on the road, Cat Boy uses his cat ears to hear Luna Girl laughing and he steers to the right. When the PJ Masks go out, Owlette uses her owl eyes to spot Luna Girl and her moths (holding a bag full of Valentine's Day toys and cards) at the candy store stealing boxes and bags of chocolate.
Catboy orders Luna Girl to leave the boxes of chocolates alone and give the other Valentine's Day gifts back. But Luna Girl refuses as she keeps using her Luna Magnet to steal more chocolate boxes and then she and her moths move to the flower shop to steal pink, red, and white roses. Gekko thinks that if they could get the Luna Magnet from Luna Girl, then she won't be able to steal any more Valentine's Day things. Using her super owl wings, Owlette uses her owl wind to blow the Luna Magnet out of Luna Girl's hand.
Catboy begins to pounce to get the Luna Magnet away from Luna Girl but before he could grab it, the moths stop him and tickled him until he started laughing. While Catboy was down, Owlette swoops down to grab the Luna Magnet but she too was tickled by the moths and she dropped the Luna Magnet as Luna Girl went to pick it up. Now Fish Boy and Gekko were the only ones left not being tickled, so they quickly shooed the moth swarms away from their friends before Luna Girl flew away on her Luna Board. After she sand her moths left, the four PJ Masks hop back into the Cat Car to chase Luna Girl.
When they caught up with her, they find Luna Girl stealing Valentine's Day decorations while the moths were secretly eating all the chocolates from the boxes. Gekko uses his super gecko camouflage to sneak up on Luna Girl and snatch the bag away from the moths, then he uses his super gecko muscles to carry it. But suddenly, one of the moths spotted the bag being lifted and realizes that Gekko is trying to take the bag away from Luna Girl. Quickly, he flies over to Luna Girl and points the direction to where Gekko is as Luna Girl points her Luna Magnet at him.
Luckily, Gekko turns visible again and dodges it just in time but he tripped over an empty chocolate box and fell flat right on his tummy. Luna Girl points her Luna Magnet at Gekko again but just as the beam was about to hit him, Fish Boy uses his super fish bubble to protect both him and Gekko that the beam bounced off and was now heading towards Luna Girl. She dodges it just in time just as the beam shot into the sky.
Furiously, Luna Girl calls for her moths but they were now sick from eating too much chocolate. She decides to battle the PJ Masks by herself as she rides her Luna Board towards them but behind her, Catboy uses his super cat jump to grab her Luna Board like last time. Luna Girl tries to shake him off, but Catboy was holding on as tight as he can while Owlette flew over to Luna Girl and tried to get her Luna Magnet. But when she turned, Luna Girl steadily points her Luna Magnet at her and now Owlette was trapped in her Luna beam.
Looking down at Gekko, Fish Boy calls for his help. Gekko knew that he had to think of some way to save his friends and Valentine's Day fast before dawn. Suddenly, he sees a light post which gives him an idea, and shouts out "Time to be a hero!" as he turns to Fish Boy and tells him that he has an idea.
While Luna Girl was busy spinning Owlette around and trying to shake Catboy off her Luna Board, Gekko calls to her at the light post as Luna Girl drops Owlette that Fish Boy had to catch her, and shoots a beam at Gekko. But Gekko dodges it in time when the beam reflects from the light's glass and it hit Luna Girl just after Catboy lets go and lands safely on his feet as Luna Girl crashes down and she drops her Luna Magnet as the beam wears off.
Catboy, Owlette, and Fish Boy come over to Gekko and congratulates him for stopping Luna Girl while nearby, Luna Girl got up on her feet and called for her moths who have recovered from their stomachache. Gekko grabs the Luna Board and Luna Magnet, then tells Luna Girl that it's all over now that he and the PJ Masks have her Luna Board and Luna Magnet, so she won't steal any more Valentine's Day gifts and chocolates. Luna Girl angrily stomps then falls to her knees, but sobs because she never has a real Valentine's Day because no one has ever given her any card, toy, or box of chocolates every year. Shocked, the PJ Masks decides that they should celebrate Valentine's Day with her, but they'll need to return all the Valentine's Day toys and cards to the shops and make new chocolates first.
So with Luna Girl's help, they managed to get everything back and make more chocolate. Then they set the all Valentine's Day decorations back up and they were finally done!
After helping the PJ Masks fix the decor, they give back her Luna Magnet and Luna Board before Luna Girl walks away miserably because she didn't get any Valentine, but then stops when Gekko calls for her and holds out a heart-shaped box of chocolates and a red rose for her. Before receiving her gifts, Luna Girl looks directly at Gekko in the eyes and she blushes as the scenery around them turned pink and sparkly. Luna Girl is basically paralyzed in love and her eyes glimmer wildly as she and Gekko began wide-eyed and started smiling brightly at each other. Eventually, they both shake their heads and come to their senses again as Luna Girl takes the box and rose from Gekko and mumbles a thank you to him.
But before she and her moths left, Gekko stops Luna Girl and asks her to be his Valentine and (nervously) asks her to go out with him to the Valentine's Day party tomorrow this evening. She somehow agrees and finally she and her moths flew off before Gekko and his friends shouted hooray and jumped with joy.
Later the next evening, everyone was already in the manor having fun and enjoying the party while Gekko was waiting anxiously at the entrance for Luna Girl. He was thinking that maybe she decided not to come to the party when suddenly, Luna Girl appears wearing a sparkly lunar dress and she had a moon hair clip on her hair while her moths wore mini black bow ties. Smiling at her beauty, Gekko holds out his hand to Luna Girl and she accepts it as they held onto each others hands and walked into the manor together.
After having their Valentine's Day picture taken, the young pair heads to the foods table where Gekko's friends were chatting happily just when they saw him with Luna Girl and her moths, who were enjoying chocolate from a nearby chocolate fountain. Luna Girl lets go of Gekko's hand as she introduces herself to them while Gekko goes to get two cups of love potion fruit punch (without the love potion in it) when suddenly, he slips on a chocolate banana peel and soon, finds himself lightly kissing Luna Girl after almost crashing into her. They apologize and laughed shyly with each other just when slow dancing music began to play.
Everyone goes to the dance floor and they started slow dancing with each other. As everyone danced, Gekko asks Luna Girl "May I have this dance?" and Luna Girl shyly replies "Yes." as she and Gekko walk to the dance floor and started slow dancing with each other too. It was the best Valentine's Day night they've ever had!
- The episode shows that Luna Girl has a crush on Gekko.
- Valentine's Day is the second holiday Luna Girl celebrates with the PJ Masks.