This episode part is preceded by Search for Ruby!.
Airi's childhood friend Laura Fukuoji arrives from abroad to visit. Laura asks Airi to protect a valuable stone in a museum, but she and her partner Luea are actually setting a trap to steal Airi's pendant.
Cut off from the Jewel Palace, Airi tells the entire Jewelpet gang they can stay at the detective agency until they can find a way back home. Larimar asked everyone about the transformation magic that they've seen earlier. Referring to her pendant, Airi commented that her father bought the stone overseas. Labra tries touching the stone, but seemed to herself that she can't transform. Ruby boasts to herself that she can transform again. She places her hand on the stone for a brief moment, but nothing happened, much to her surprise.
Discussing about Ruby's slumber, Ruby replied that she was in training with a Jewelpet named Luea and fell asleep at some point while with her. Larimar then realized Luea also disappeared seven years ago. Then, a doorbell rings and Airi comes to the door to answer it. Opening the door, a girl in a blue dress greets Airi. But Airi appears to not recognize her, much to her annoyance.
Later, Airi realizes her name is Laura, a girl who was away for France. Laura said she came to have her solve a case for her. She presented her a letter that came to her mansion: It reads that a thief is plotting to steal from the Fukuouji. Forewarned of the thief's plot, she takes the case with sheer determination. Laura thanks Airi for her help, only for her to look slyishly.
Later, at the manor of Laura's home, she came to a black rabbit known as Luea herself on top of the building informing that Airi took the case and didn't realize it's a trap. They then take a yonder look at the Jewel Palace in the distance, where Laura commented it not being there the last time she was at home. Luea explained that the palace fell from the sky when it broke through the barrier between Jewel Land and the Human World and came crashing down in the town. The humans try to investigate palace, but they are unable to enter or interact with it at all. So it was treated as an everyday object where the people paid no attention to it at all. Luea also explained that the reason for the palace falling is because the magic in Jewel Land was growing weaker. So, the Jewelpets were sent into training to grow their magical powers to save their home.
Like all the other Jewelpets, Luea was sent out into the Human World to train and grow their magical powers. She was sent along with Ruby, where they vigorously competed with each other. But as Luea gone way ahead of her, she was shocked and upset that Ruby is gone. She searched around endlessly for her but collapsed from exhaustion. That's when Laura, her partner, found her in the streets of Paris and saved her. Laura commented how she ended up getting lost in Paris, but Luea changes the subject commenting about Ruby's spectacularly magic she saw the other day. Taking note of the pendant that changed her, Luea plots to use it for herself that can also change her into a human as well.
Back at the agency, Airi informs her brother that they will be out for the time being. But Ruby stops her, saying that she wants to eat dinner before they leave. Airi says they don't have any time to do it right now, so the brother decided to order pizza for them. But Airi also stated it takes time to have it delivered too, even thinking it needs 'magic' for that to happen. Getting the idea, Ruby decided to cast magic to make "Magical Pizza" appear. She creates a set of ingredients to make a pizza so she can cook pizza for everyone. However, Airi insists they don't have time at all and drags her away.
The gang heads for Laura's manor looking for the thief in the Jewelry room. Airi notices there aren't any security guards, but Laura says they "hiding in the shadows." Airi asks where the Legendary Treasure the thief plots to steal. Laura shows her the treasure: A pendant that actually looks similar to Airi's pendant to everyone's surprise. Luea, disguised as a "thief" and appears to be hiding in a vent, says to herself that the pendant is actually fake and will be used to switch out her real pendant.
As Airi and Laura compare their pendants, Laura has an idea of switching out her pendant with her own, knowing that 'her' pendant might be safe with Airi. Seeing the opportunity, Luea turns off the lights and snatches the (real) pendant from the case and escapes through the window. The gang goes after her and catch up to her on top of the manor roof. Luea boasts to herself that with the pendant, she'll be able use its power and gain strong magical powers. However, as she tries to use the pendant, she discovers it's not working as it would've expected. As she frets in frustration, Larimar sneaks up close and tackles her down, causing her to drop the pendant. Airi dives and catches the pendant, but Luea grabs it too. They end up struggling over the pendant, while Ruby joins in to assist.
Laura catches up to everyone, only to worry that Luea is having a hard time. Suddenly, Laura slips on the roof and hangs on the roof's edge. She's nearly losing her grip and Luea becomes distressed. But then, the pendant starts to glow. Getting the signal, Airi combines the pendant with Ruby and transforms into a human girl via "Magical Change." With her Jewel Flash magic, she makes a giant stuff rabbit appear and saves Laura from falling. Returning to normal, Larimar unmasks Luea and reveals her true identity. Ruby embraces Luea after reuniting with her, also telling her that it's bad to steal from other. Luea admittedly acknowledges her.
As everyone returned to the ground, Ruby says she'll forgive Luea. Luea nervously thanks to everyone for saving Laura. Ruby acknowledges her and then the gang parts ways. As they leave, Luea vows that she'll still get her hands on Airi's pendant and make the transformation magic hers.