A bus speeds uncontrollably through the streets of Paris, and is unable to brake, until Ladybug and Cat Noir show up, and work together to stop the bus. Cat Noir throws his baton to Ladybug and she catches it as she lets herself fall under the bus, then wraps her yo-yo string around the baton, and after securing her yo-yo to the bus, tosses the baton back to Cat Noir. He extends it and lets it get caught behind two lampposts, effectively stopping the bus just before it hits August, his mother, and another civilian. As Ladybug and Cat Noir help the passengers exit the bus, he suggests to Ladybug that they have a superhero dinner "rooftop style". She smiles and tells him that she would love to, but she already has plans with her friends, and most likely wouldn't make it.
Over at the Dupain-Cheng residence, after finishing dinner, Marinette's father produces Marinette's favorite cake decorated with lots of fruit. Marinette thanks him, but politely declines, reminding her parents of her plans to go out for ice cream with her friends. Her parents wax romantic about André's ice cream, sharing the story of how Tom put an engagement ring into their vanilla ice cream to propose to Sabine. According to popular legend, whoever shares André's ice cream will fall in love forever. Marinette leaves, blushing after her parents ask her who she plans to share ice cream with.
At the Agreste mansion, Adrien is sitting alone in his dining room, waiting for his father to eat dinner with him. He texts Nino just before Nathalie comes in to inform him that his father will be having dinner alone in his office. Adrien leaves, grumbling about how his dad makes him wait and never bothers to show up. Nathalie reminds him to practice his piano. Up in his room, Adrien plays his piano soundtrack to give the impression he is practicing, as he tells Plagg of his intention to go out as Cat Noir and prepare his planned dinner with Ladybug, since she did not say no outright. Plagg reminds him that she did not say yes, either. Adrien then transforms, and escapes out the window.
Marinette meets up with Alya, Nino, Mylène, and Ivan at the Trocadéro as planned. She is disappointed to find out that Adrien's father has forbidden him from going out that evening. Nino gets a notification that André, who has to be tracked down before you can buy ice cream from him, has set up shop on the Pont des Arts bridge.
Meanwhile, Cat Noir is setting up a lovely romantic scene on a rooftop not far from Marinette's house, complete with dozens of candles and red rose petals. Once it is completed, he sits down to wait for Ladybug, still hoping she will come despite her saying earlier that she probably wouldn't make it.
On the Pont des Arts bridge, André creates specially crafted ice creams for all the young couples. Mylène and Ivan share a chocolate-praline-nougat ice cream, and Alya and Nino share one of coconut, banana and passion fruit. Tikki encourages Marinette to get some, saying she could share it with her, but Marinette is still despondent about Adrien not being able to come. André attempts to cheer her up by crafting her an ice cream of her own, "peach pink like his lips, mint like his eyes." He promises her that if she eats it, her lover will come. Marinette is distracted by a boy with the same shirt as Adrien, and her ice cream gets knocked out of her hand as his friend rushes toward him. André tries to reassure her, claiming that the ice cream has to be eaten for the magic to work. He quickly makes another one, but Marinette sadly declines it, even saying his ice cream isn't magical, that it's just normal ice cream. She departs, dejected, and her friends also leave.
.André is left devastated, and slumps to the ground, crying about his ice cream never failing before. Hawk Moth appears in his lair, and sends an akuma to André. André transforms into Glaciator, a giant ice cream snowman, and he begins to freeze people into ice cream, except when he sees a couple, whom he leaves alone.
.At home, Marinette is ashamed of herself for being rude to André and ruining her friends' evening. Tikki comforts her, telling her everyone makes mistakes and that she'll be able to eat ice cream with Adrien another time. She sighs at Tikki, and climbs out onto her balcony. Tikki comes up after her for a moment but, sensing that Marinette needs to be alone, sinks back down. On a nearby building, Cat Noir has given up waiting for Ladybug and sadly blows out his candles, one by one, asking if Ladybug loves him in a Daisy Oracle style, leaving only one lit, one that symbolizes "She loves me not". He stares down at the candle, utterly heartbroken, until he finally looks up, and sees Marinette on her balcony.
Cat Noir jumps to a perch behind Marinette and greets her, apologizing for startling her. She asks him if he has "superhero-stuff" to do, and he explains that he doesn't feel like "being a superhero tonight", and asks if he can stay with her for a while. Marinette accepts, and they fall into a comfortable conversation. Cat Noir tells Marinette how he prepared a dinner for Ladybug, wanting to make something special for her, only to have her not show up. Marinette realizes that Cat Noir is really in love with Ladybug. After he discovers that she also has a broken heart, he ends up taking her to the place he prepared for Ladybug, lighting all the candles for her, and showing a sensitive side she is unfamiliar with. She says it's beautiful, and that she's sorry about his disappointment.
He says it's not her fault, and she restates herself by saying she's sorry for Cat Noir because he took the time to prepare all of it for his partner, but she didn't show. Just as Marinette tries to cheer Cat Noir up by suggesting that some problem may have kept Ladybug from coming, Glaciator appears nearby, firing ice cream at Marinette, which Cat Noir blocks with his spinning baton. When they escape the scene and hide, he asks if another villain has fallen in love with her, but she says no, and that it's André the ice cream seller. Cat Noir states that Glaciator doesn't look very sweet at the moment, to which Marinette simply says, "It's a long story." Meanwhile, as Glaciator fires his ice cream all over the streets, Cat Noir carries her back home and drops her off on her balcony. He says he wants to keep her safe and that he'll lead the villain away; but before he leaves, Marinette grabs him by his tail, and thanks him for cheering her up. He tells her it's the least he could do, and leaps away. Marinette and Tikki comment on Cat Noir being so thoughtful, before she transforms.
Cat Noir confronts Glaciator, but gets sent flying along with a police car until he is caught by Ladybug's yo-yo string. He bitterly asks her how her "other plans" went, but she doesn't answer, startled by his harsh tone. As the fighting continues, they see that all the ice cream is coming from Glaciator's hands and deduce that the ice cream scoop is the akumatized object. Taking cover behind a building, Ladybug sees that Glaciator won't attack couples, and tells her partner, to which he replies, "Too bad for us." She says that he doesn't understand, and that they could pretend to be a couple themselves. However, Cat Noir icily states that he doesn't like to play with feelings, and goes to attack the villain, but fails. Ladybug defends him, and realizes that he is still upset that she didn't come for their date. Behind a flipped car, she apologizes to Cat Noir as she didn't intend to hurt him. Cat Noir then apologizes to Ladybug for over-reacting, and agrees to follow her plan to defeat Glaciator. Giving her "couple" idea a try, the duo walks towards the villain, Ladybug holding Cat Noir's arm and kissing him on the cheek, which she tells him is just part of the plan. Seeing them defenceless, Hawk Moth orders Glaciator to attack, but he refuses because they are in love. Once close enough, Ladybug throws her yo-yo at Glaciator and, upon hitting something inside, discovers that André isn't the monster as such, but is inside it.
She gets pulled by the villain until Cat Noir cuts him down, and they take cover behind a nearby building. Needing to hurry before everyone melts, Ladybug summons her Lucky Charm, and receives a motorcycle helmet. Using the objects around her, she has the idea to make a propeller, and with Cat Noir's Cataclysm, they are able to blow all the ice cream off of André. Cat Noir grabs the akumatized scooper and tosses it to Ladybug, who smashes it on the ground. Once the akuma is released, she purifies it and uses her Miraculous Ladybug power to return everything to normal. André is amazed that he has been saved by a superhero couple and hugs them both. Seeing Ladybug smirking at this, Cat Noir shrugs and says that it was André who said it, before grinning up at him. Hawk Moth, meanwhile, vows revenge.
Arriving at the date spot, Ladybug tells Cat Noir that his set-up is amazing, and that she is glad she came, but also says that she doesn't want to play with his feelings or lie to him. Ladybug says she considers him not merely her partner, but also a dear friend. He asks her why she's talking about lying to him, and she honestly tells him that her heart is set on someone else. When Cat Noir asks who, she doesn't answer, explaining that they have no choice but to keep their personal lives a secret. Holding a red rose, Cat Noir gives her a sad look. Then, stepping right up next to her, he smiles warmly at Ladybug and gives her the rose, telling her that he understands, and that she's his best friend too. He kisses Ladybug on the cheek, startling her slightly, and tells her she can keep the rose, as it goes with her costume, before taking off and leaving her gazing at where he'd just been and blushing. She then turns around and watches him leave, stunned.
Back in his room, Adrien plops down on his bed as Plagg tells him that if he is lovesick, the only way to feel better is to eat cheese; but Adrien replies that he's not lovesick, and he is sure Ladybug will love him as much as he loves her someday. Also, he accepts that his friendship with her as the greatest gift he can have at the moment. This much talk about love makes Plagg sick and desperately in need of Camembert.
The next day, Marinette arrives at André's ice cream stand on another bridge, delighting him with her presence. He then offers to make her another cone, the same combination as before, which she finds delicious. When he asks her if she still doesn't believe that his ice cream can lock two loves together, she says, "never say never" and wishes André a good day. Sitting down at one end of the bridge, she shares her ice cream with Tikki, which the kwami finds tasty. Meanwhile, Adrien arrives at André's stand from the opposite side of the bridge, having heard that his ice cream is magical, and André asks the boy what he thinks. He says one has to believe, making André happy, and he gives Adrien a cone in the design of Ladybug, on the house. Adrien, also wishing André a good day, walks back to his side of the bridge, opposite Marinette's end, before the ending card appears.
Major characters
Marinette Dupain-Cheng/Ladybug
Adrien Agreste/Cat Noir
Gabriel Agreste/Hawk Moth
Tikki
Plagg
Akuma
André/Glaciator
Minor characters
Tom Dupain
Sabine Cheng
Nathalie Sancoeur
Alya Césaire
Nino Lahiffe
Ivan Bruel
Mylène Haprèle
Wayhem (non-speaking)
Adrien's bodyguard (background)
August's mother (background)
August (background)
Jean Duparc (background)
Chloé Bourgeois (pictured)
Sabrina Raincomprix (pictured)
Rose Lavillant (pictured)
Juleka Couffaine (pictured)
Lê Chiến Kim (pictured)
Max Kanté (pictured)
Alix Kubdel (pictured)
Nathaniel Kurtzberg (pictured)
Caline Bustier (pictured)
Mr. Damocles (pictured)
Aurore Beauréal (pictured)
Mireille Caquet (pictured)
Civilians