When the student is ready, the teacher shall appear.
"Furious Fu, I am Shadow Moth. That heartless thief has disrespected you and your partner. I'm giving you the power to make him pay, show him who is in charge! All I ask in return are Ladybug and Cat Noir's Miraculous!"
— Shadow Moth
Master Su-Han, a Guardian of the Miraculous, appears to Marinette and demands the return of the Miracle Box if she can't prove that she was entrusted it by Master Fu. The problem is, Master Fu has amnesia.
Tropes:
- Accidental Misnaming: Due to having amnesia, Fu refers to Ladybug and Cat Noir as "Lady Beetle and Mr. Bat."
- Amnesiac Resonance: Fu paints a very abstract painting for Marinette, saying that he doesn't understand the painting's significance, but for some reason it came to him and reminded him of her. The painting is mostly red with black spots.
- Furious Fu/Master Fu calling to Cat Noir "a wingless bat"; his Astro form has bat shaped wings.
- Armor-Piercing Question: Ladybug asks Su-Han whether he intends to sit back and watch while she and Cat Noir try and correct his mistake (i.e. subdue and de-evilize Furious Fu, who was akumatized because of Su-Han's actions). This shames Su-Han into fighting again.
- Awesomeness by Analysis: Furious Fu has his own "AMP Factor" sequence after writing "Vision" with his paintbrush.
- Bait-and-Switch: Another episode where the Akuma victim was not the intended target. Su-Han's rage at being defeated and tricked by the heroes has Shadow Moth send an Akuma for him, but he uses a Guardian focus technique to shield himself from it causing it to target Fu instead after Su-Han came up him and forcefully took his staff.
- Call-Back:
- The episode follows up on what the amnesiac Master Fu has been up to after the end of Season 3, with him having since married Marianne and moved to London with her.
- Hawk Moth previously noted that Ladybug and the other Miraculous users have yet to unlock their full power and that part of it is because they're children. Su-Han reveals that the Miraculous were meant for adults and not for children.
- Su-Han reveals that some of the rules of being a Guardian of the Miraculouses includes not letting the Kwamis live outside of the Miracle Box, Guardians not being allowed to lose Miraculouses, nor are they allowed to wear Miraculouses under any circumstance, and to not involve civilians in fights. Outside of Marinette allowing the Kwamis to live outside of the box, we've also had Master Fu using and losing the Peacock Miraculous as well as losing the Butterfly Miraculous, and Ladybug and Cat Noir getting help from civilians to fight akumas in various episodes.
- Su-Han mentions that Plagg wiped out the dinosaurs, which Master Fu previously mentioned. There also used to be dragons that Plagg similarly drove to extinction.
- Shadow Moth addresses Fu by name and mentions they are meeting again, although Fu doesn't remember him. He's referring to when he met and battled Fu in Season 3's finale.
- One of the reasons why Su-Han considers Fu to be a failure is his inability to spend a whole day without eating.
- Charles Atlas Superpower: Su-Han has this, as shown when he helps Ladybug and Cat Noir fight Furious Fu, and he explains that Guardians are trained in a special kind of martial arts known as Mirakung Fu.
- Crippling Overspecialization: Mirakung fu is an art designed to allow guardians like Su-Han to fight Miraculous users without any explicit super powers. And only Miraculous users. When forced to fight Furious Fu, he initially runs and hides, and when encouraged to fight anyway, he gets defeated in short order.
- Drill Sergeant Nasty: Su-Han had many demeaning names for Fu when he was his student such as Whiny Chicken Leg, which he continues to call him in the present. Even at the end of the episode he still has difficulty remembering to call him by his actual name.
- Fish out of Temporal Water: Having only been recently revived after a century in stasis within Feast, Su-Han is baffled by modern technology such as televisions and cell phones. Ladybug uses this to distract him by playing a video on her yo-yo then roping the Miracle Box as he searches for the source of the sound.
- Heroic BSoD: Su-Han has a brief moment of despair, wondering if he's the only one who considers Plagg running loose to be a terrible thing and naming a few of the catastrophes Plagg accidentally caused over the eons. He quickly composes himself and decides to take the Miracle Box back, along with the Ladybug and Cat Miraculouses.
- Meaningful Name: Mirakung fu is derived from "miracle" and "kung fu".
- Meaningless Villain Victory: Of a sort, as Shadow Moth finally gets his hands on Fu, something he'd tried all of the last season to accomplish. However, because of Fu's amnesia, he can't get any of the information about the Miraculous or the heroes' identities out of him that he wanted so badly, giving him nothing but a typical akumatized minion, albeit a fairly powerful one. The episode also reveals that Guardians have a technique to shield themselves from being akumatized, meaning he'd never have been able to control him when he had his memories in the first place.
- Mutual Disadvantage: Invoked by Ladybug, who causes herself, Cat Noir and Furious Fu to be all stuck together, which is fine by her since she called Marianne ahead of time to break the paintbrush Furious Fu's akuma was in while everyone was immobilized.
- Noodle Incident: Su-Han brings up Plagg's responsibility for the extinction of the dinosaurs once again, and adds that he also caused dragons to go extinct.
- No-Sell: The Guardians have a focusing chant that shields them from being affected by an akuma. Su-Han uses it to stop the akuma from taking control of him.Su-Han: My anger is mine, but I am not my anger.
- Oh, Crap!:
- Su-Han takes the news of Nooroo and Duusu being in the hands of a villain in relative stride, merely bemoaning Fu's incompetence, but freaks out upon learning that Plagg is wandering freely around Paris and Marinette doesn't know the civilian identity of his owner, even if they're familiar on a professional basis.
- Su-Han freaks out upon seeing an akuma and quickly shields himself through a focusing chant. He then books it when Fu falls victim to the akuma.
- Paper Talisman: Furious Fu's power allows him to draw words on paper talismans that then have the power of that word. He demonstrates the ability to track people, summon lightning, teleport, and stop time for someone using them.
- Proverbial Wisdom: Su-Han speaks like this a lot, as does Furious Fu.
- Puppy-Dog Eyes: Kwamis, unsurprisingly, turn out to be really good at those when they convince Marinette to let them see Master Fu.Xuppu: Operation Kwami Baby-Doll Eyes!
- Reasonable Authority Figure: Su-Han agrees to let Marinette keep the Mother Box at the end because her methods, though unorthodox and in defiance of Guardian rules, are effective and her instincts are sound.
- Screw the Rules, I'm Doing What's Right!: Cat Noir reluctantly agrees to give up his Miraculous if Ladybug asks him to, but when Su-Han also demands she give up her guardianship of the Mother Box, which will wipe her memory, he immediately refuses any further cooperation.
- Screw This, I'm Outta Here: Su-Han is mopping the floor with Ladybug and Cat Noir, but quickly quits the field when Furious Fu arrives, noting that his mirakung fu is effective only against Miraculous users, not people empowered by an akuma. A well-placed question by Ladybug convinces him to rejoin the fight.
- Scry vs. Scry: Furious Fu uses his powers to copy Ladybug's sense of how her Lucky Charm is supposed to be used and uses that to intercept the attempt. Then Ladybug reveals it was just meant to be a distraction for Marianne to sneak in behind him and grab his brush.
- Sparse List of Rules: Su-Han states that there are at least 133 rules to being a Guardian and he only explains four of them — Rule 14 is that Kwamis aren't allowed to live outside of the Miracle Box, Rule 52 is that Guardians aren't allowed to lose Miraculouses, Rule 133 is that Guardians are also not allowed to use Miraculouses regardless of the situation, and an unknown numbered rule about not involving civilians in battles. As far as we can tell, Master Fu and Marinette have already broken a few...
- Spoiler Title: The episode is called "Furious Fu", so when the akuma first goes for Su-Han, it's obvious something is going to redirect it to Fu. Sure enough, it turns out Su-Han has a focus chant to ward it away, and Fu gets akumatized instead over Su-Han's behavior towards Marianne.
- You Are Better Than You Think You Are: Cat Noir says this to Ladybug when she begins to despair over their failure to defeat Hawk Moth, adding that he wishes she would believe in herself the same way he believes in her.
