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Catalyst (Heroes' Day - Part 1)
Released on December 2018 (Netflix)[1]

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"Catalyst (Heroes' Day - Part 1)" is an episode of Season 2 of Miraculous: Tales of Ladybug & Cat Noir, and it is the first part of "Heroes' Day".[5][6] It's world premiere was on October 21, 2018, in Switzerland for French viewers on RTS Deux.[3]


Coming soon!


After facing another supervillain late at night, Marinette and Adrien go home and fall asleep. However, they are soon awoken only seconds later and reminded that it's Heroes' Day, a day where every Parisian has to do a good deed in honor of their superheroes. Marinette panics since her time as Ladybug prevented her from preparing hers, but she is saved by Tom and Sabine, who give her a box of macarons to give to her classmates.

Meanwhile at the Agreste mansion, while getting ready for school, Adrien sees his father through his bedroom window staring at a stone statue of Emilie Agreste. As he goes downstairs, Nathalie tells Adrien that she booked the Chinese and fencing rooms for him as he requested. After Adrien leaves for school with his bodyguard, Nathalie goes to talk to Gabriel and tells him that it's time to implement his plan, pointing out how his target, Lila Rossi, has had months to ponder her anger over Ladybug. Gabriel asks Nathalie if she's really okay with helping him, to which Nathalie says that she'll always be there for Gabriel. 

At school, Lila speaks to Miss Bustier's class through a video chat. She tells them that she is in the country of Prince Ali and had been invited by him to his palace. Marinette, aware of Lila's deceitful nature, attempts to expose her lies by pointing out that Prince Ali is in the USA, but Lila says that Prince Ali wasn't actually with them. Marinette vows to herself that she'll expose Lila's lies one day, but Alya, who overhears, believes that Marinette is just jealous because Lila had once tried to date Adrien. When asked by Miss Bustier what she prepared for Heroes' Day, Lila says that she has received permission from other countries to work on a project to reduce pollution and is meeting with Prince Ali to get his approval. She then claims that she has to go because it is getting late where she is.

Once she hangs up, it is revealed that she actually still lives in Paris and is hiding in her room. When her mother comes in and asks who she was talking to, Lila says she was talking to her boyfriend Adrien. Lila's mother also asks her about the school, to which Lila claims is closed from all the akuma attacks. Lila's mother then receives a call from Mr. Damocles, but Lila convinces her not to answer it since he's probably been akumatized. The two are then interrupted by the noise of the ongoing Heroes' Day Parade, which irritates Lila.

Miss Bustier tells the class that even if they don't have Prince Ali as a friend, there are other ways to do good deeds. Mr. Damocles bursts into the room dressed as The Owl and talks about how Ladybug and Cat Noir have saved Paris from Hawk Moth. He then asks everyone what heroic deeds they're doing. Nino says that he will be playing music for the retirement home. Adrien says that he will give a Chinese lesson to his fencing class and a fencing class to his Chinese class. Alya says that she has met with the mayor to discuss building handicap facilities. Hearing everyone's good deeds makes it hard for Marinette to admit that all she did was bring macarons for the class. Chloé mocks Marinette for doing so little, but Alya defends her by saying that it's better than nothing. Angry that Alya would imply that she didn't prepare anything, Chloé says that since she is a superhero, she is offering her autograph to anyone who wants it. However, Marinette still feels embarrassed by not having much done, so she tells the class that she is organizing a party for the whole school with countless amounts of pastries.

Once home, Marinette asks her father for help in making the treats, but he cannot since he has to finish baking a giant Ladybug treat for the mayor. Sabine advises Marinette to just be honest with her classmates, but Marinette decides to make the treats herself instead. 

Back in his lair, Nathalie and Gabriel wait for the first part of their plan to unfold. In her room, Lila angrily scrolls through a bunch of news feed about Ladybug until coming across an interview with Gabriel and Nadja Chamack. In it, Gabriel announces that he is funding a movie about Ladybug's honor due to saving him and his son countless times. After saying Volpina is a false hero in comparison to Ladybug, Lila throws her laptop against the wall in rage. With her negative emotions hitting their peak, Gabriel transforms into Hawk Moth and sends an akuma to Lila. It infects her bracelet and Hawk Moth offers her the power of illusion once more. Lila agrees and is transformed back into Volpina.

With her illusionary powers, Volpina sends an illusion from up in the Effiel Tower: an akumatized Ladybug with inverted colors and Cat Noir appear on a Ladybug float. 

Akumatized Ladybug and Cat Noir duel, with the latter warning everyone to stay back from his possessed friend. The two fight briefly until Cat Noir tries to use his Cataclysm power on the yo-yo to stop her. However, "Ladybug" proves too fast and pulls him towards herself and plants his hand on his own chest: Cat Noir disintigrates into black dust in front of everyone. Akumatized Ladybug picks up the fallen Miraculous and proclaims she is going to give it to Hawk Moth. 

With the people of Paris drowning in despair, Hawk Moth seizes his opportunity to continue the second part of the plan. He deakumatizes Lila, reverted the akuma to normal, then creates another akuma in his lair for Nathalie. It infects her tablet and tranforms her into Catalyst, a villian who has the ability to multiply Hawk Moth's akuma corruption power to create as many corrupted akumas as he wishes. Catalyst touches Hawk Moth's staff, which transforms him into the Scarlet Hawk Moth. With his augumented powers, Scarlet Hawk Moth sends a swarm of akumas all over the city.

Marinette, who is at home, continues to attempt to create her Heroes' Day pastries deed as she promised her classmates. She pleads with Tikki to let her transform into Ladybug and use her Lucky Charm to help her with her task, but soon realizes that she can't use her powers for her own personal needs. 

Marinette returns to school, dreading returning to disappoint everyone, just as Adrien catches up to her and tells her he will be able to attend her party. The two find themselves in bigger problems, as numerous students have seen the illusion fight between the "akumatized Ladybug" and "Cat Noir".In the middle of a live interview between Nadja, Jagged Stone, and Clara Nightingale, the three are akumatized back into their former akumatized selves just as numerous red akumas descend on the school, akumatizing other students. Marinette realizes that the akumas are infecting those who are afraid and warns the other students not to show fear. Juleka is nearly akumatized by after hearing Marinette's warning, she calms down. Alya and Nino also comfort one another to prevent themselves from being afraid. Alya then calls her sister Nora and tells her not to be afraid, but Nora confidently tells Alya that fear is afraid of her as she smashes a bunch of akumas with a broomstick. Meanwhile, Marinette runs into the locker room, transforms into Ladybug, and heads straight to Master Fu for additional help.

Adrien tries to find a place to transform but is soon captured by his bodyguard, who has turned back into Gorizilla. By Hawk Moth's command, he forces him to keep Adrien safe, while instructing Sabrina, now Vanisher once again, to follow Ladybug to the Guardian of the Miraculous. As Gorizilla takes Adrien away from the battle, Plagg sneaks behind the villain and blows on the ground, causing it to crack and making Gorizilla trip and drop Adrien. Once he gets away from him, Adrien transforms into Cat Noir. 

Meanwhile, a suspicious Ladybug realizes that she's being followed and ducks inside of a sewer. She sees Vanisher's footprints in the water, uses her yoyo to tie her up, and then purifies her akuma, turning her back into Sabrina. Sabrina is delighted upon seeing the real Ladybug and promises to tell everyone the truth while Ladybug heads over to Master Fu. Once there, Master Fu voices how much he's feared the day Hawk Moth would realized how much power he actually has and then takes out the Miracle box for Marinette to choose a trusted ally to help her. 

Ladybug finds Alya and Nino hidden back in the school's lockers. Lacking a good excuse to seperate them, she gives them their respective Miraculoses, revealing their superhero identities to each other. Nino is more shocked than Alya, who tells him she always believed in his heroic potential. The two then transform into Rena Rogue and Carapace.

Chloe, in the meantime, has set up a "Bee Signal", somehow unconvinced of the parade fight. Cat Noir shows up and coerces Chloe to ask for the Miraculous politely and gives it to her, allowing her to transform into Queen Bee again.

With all five heroes united, they all arrive at the Trocadéro, where Queen Bee asks why they are waiting, with the akuma army nearby at the tower. Ladybug retorts she wants to wait to see what they are planning, just as Scarlet Hawk Moth arrives, apperantly out of his lair, with Catalyst remaining behind. He broadcasts himself on TV and asks Ladybug and Cat Noir how they plan to fight his massive army. As the heroes bicker how they will approach the fight, Cat Noir asks Ladybug what her plan is. She looks onward wordlessly. The episode ends with a red variant of the Hawk Moth logo, flashing with the Catalyst version of his butterfly mask.


Major characters

Minor characters


  • This episode reveals that, aside from Adrien and Marinette, no one knows about Lila's compulsive lying.
  • Akumatized Ladybug shares the same color inverted costume as Antibug
  • This episode shows Hawk Moth removing someone's powers, for the first time.
    • This episode shows an akuma leaving its host without Ladybug destroying an object or purifying said akuma. This is also the first time the affected has not shown signs of confusion or fatigue.
  • Akumatized villains from Season 1 and Season 2 return in this episode, but their designs are colored red.
  • This is the second time Plagg uses Cataclysm.
    • He seems to be proud of the fact he learned to control it better, thus keeping the damage to a minimum.
  • This episode has shown the most transformation sequences, having a total of six transformations, surpassing "Sapotis" and "Anansi", which only had three and "Queen Wasp", which only had four.
    • With this, all Miraculous users introduced up to this point transform in a single episode.
  • A new version of Alya's transformation sequence is shown when she transforms in her everyday attire.
    • Also Rena Rouge's eyelids are now black whenever she blinks as opposed to "Sapotis" where her eyelids remain uncolored.
  • During Nino's transformation, Carapace's theme changed, compared to his transformation during "Anansi".
  • Nino discovers Alya's superhero identity, and her knowledge of his, which she appeared to gain in "Anansi", is confirmed.
  • Rena Rouge, Carapace and Queen Bee return in this episode to assist Ladybug and Cat Noir in their mission.
    • This also marks the first instance where all superheroes appear at once.
  • The Lucky Charm and Miraculous Ladybug are not used in this episode.
    • This the first time Ladybug doesn't call on her Lucky Charm.
  • This is the first episode in which the main akumatized villain isn't defeated or cured.
  • This is also the first episode where Hawk Moth leaves his lair while he is transformed


  • Alya's bangs are miscolored throughout the episode.
  • Marinette doesn't have her earrings at one point when she's in the kitchen.
  • When Marinette is showing her father the list of treats for the party, her eyes are green instead of blue.
  • When Volpina gets deakumatized by Hawk Moth, the tips of her hair are brown instead of white.
  • Ladybug gives Cat Noir just the Bee Miraculous by itself, but when he gives it to Chloé, it's in the box.
  • Though Lila's mother is shown to be Clara Contard, it was said by Thomas Astruc to be an animation error.[7]
  • When Rena Rouge transforms, her eyelids are normal. However, after the transformation, her eyelids turn black.
  • As in Malediktator, Chloé's sunglasses are on her head prior to transforming, but disappear when she transforms.
  • When Gabriel enters his lair, there are no butterflies shown, but after he transforms into Hawkmoth, the butterflies are there.
  • When Gabriel and Nathalie are in the former's lair, the window is open. However after Hawk Moth's transformation sequence, the window is shown to be closed, which led to Hawk Moth opening it once again.


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  2. Twitter User "@Miraculous World Network" posted a tweet pertaining information of upcoming episodes, including an image of the production codes for the remaining 9 episodes of Season 2, after an email response from Family Channel that can be seen here, whilst the direct image itself can be viewed here.
  3. 3.0 3.1

ve Episodes
Season 1
The BubblerMr. PigeonStormy WeatherTimebreakerCopycatThe PharaohLady WifiThe EvillustratorRogercopDark CupidHorrificatorDarkbladeThe MimePrincess FragranceThe Origins Story (Ladybug & Cat NoirStoneheart) • AnimanSimon SaysPixelatorGuitar VillainKung FoodGamerReflektaThe PuppeteerAntibugVolpina
Season 2
Released episodes

A Christmas SpecialThe CollectorPrime QueenDespair BearRiposteBefanaRobostusThe Dark OwlGigantitanGlaciatorSapotisGorizillaCaptain HardrockTroublemakerFrightningale

Future episodes

ZombizouSyrenReverserAnansiSandboyQueen's Battle (Style QueenQueen WaspMalediktator) • FrozerHeroes' Day (CatalystMayura)

Season 3
Season 4
Season 5
Unknown episodes
The Origins StoryA Christmas SpecialQueen's battleHeroes' DayLadybug in HalloweenThe Chinese Legend
Miraculous Secrets
Marinette in ParisMarinette and FashionLadybug as seen by AdrienLadyblogAdrien's Double Life
Marinette and AlyaMarinette's Double LifeCat Noir as seen by MarinetteMy Birthday PartyMarinette and AdrienMaster FuTikkiPlaggFriendsNinoMax
Future webisodes


Tales from Paris
The NotebookInspirationRepetitionBusy DayHomework Essay
Miraculous Zag Chibi
Rooftop DinnerCatnip FragranceThe ChaseCuriosity Kicked the CatCutest Cat FightFatal Posy
Future webisodes


Other media
The Mini Menace LadybugLadybug PVFirst CGI promotional videosHappy Birthday to You!Ladybug (musical)Miraculous Ladybug OVAMiraculous (film)Miraculous Ladybug (musical)Miraculous Live

Start a Discussion Discussions about Catalyst (Heroes' Day - Part 1)

  • "Catalyst" Discussion

    89 messages
    • I just noticed that plagg was proud he didn't destroy too much this time and adrien was proud of him too. I wonder how many accidents pl...
    •   Omg since Alya and Nino know about each others identities and Chloe revealed hers.... Only LB and Chat are left..... EHEM ZAG EXPLAIN.