As a self-appointed assistant to Twilight, Cozy Glow goes about her rounds to help out the various students at Twilight's school, and reminds Twilight that many of the students have gone with Rainbow Dash and Starlight Glimmer to tour Cloudsdale. In the clouds, the non-pegasi students enjoy walking on the clouds with the help of a spell cast by Starlight, but suddenly the spell gives way, causing several students to fall through the clouds. The flyers quickly save the falling students, and they make their way back to the school. Twilight and Rarity find their own magic failing, and as they consider possible solutions, Cozy suggests it may be Tirek. Spike, whose fire breath is also having problems, coughs up a letter from Celestia, requiring Twilight and her friends to come at once to Canterlot. There, they learn from Celestia, Luna, and Cadance that the magic drain is affecting all of Equestria, and a letter from Star Swirl warns that if they cannot stop the drain in three days, all magic in Equestria will fail. They agree that they should go to Tartarus and check to see if this is Tirek's fault.
Twilight and her friends prepare to leave the school, with Twilight leaving Starlight in charge. Cozy is a bit surprised, but quickly offers to help Starlight with lesson plans. The Mane 6 and Spike travel to Tartarus, and while the lack of magic makes the trip somewhat miserable, the others are able to help out. They arrive at the doors to Tartarus, but they need magic to open; fortunately, Spike finds that Cozy had packed an artifact for Twilight that can be used to open any door, but breaks after use. Once inside, the door shuts behind them, and they come face to face with the cockatrice. However, Fluttershy sees that the cocktrice, like several other magical creatures within Tartarus, have lost their powers too, part of the magic drain. With Fluttershy helping to calm Cerberus, they go to see Tirek, who appears to have been expecting them.
At the school the next day, the students are surprised that Starlight is not there; Cozy explains that she had to go on her own quest and had put Cozy in charge. Cozy offers up lots of goodies for the school, which makes Sandbar and his non-pony friends doubtful of her intent. When Cozy assigns them additional homework for being grumps, they decide to make it a homework party in the library that night. As they are studying, they spot Cozy emerging from the catacombs, and decide to follow her. She goes to the headmare's office, and as the students peak in, are surprised to see Chancellor Neighsay there. Neighsay is furious to learn that Twilight abandoned the safety of the students in a time of need, while Cozy asserts that everything is fine. He refuses to accept that they left Cozy in charge, just as they hear the students eavesdropping outside. Neighsay, still believing the non-ponies to be a threat, ties them up and locks them in a dorm room, but just before he leaves, Sandbar asserts he doesn't want to be part of the non-pony group anymore, and Neighsay lets him go. Sandbar sneaks out of the school and makes his way to Sweet Apple Acres as to get the help of the Cutie Mark Crusaders. Once in tow, Sandbar and the Crusaders sneak back into the school and enter the catacombs.
At Tartarus, Twilight grills Tirek on what he knows about the magical drain. He admits that he told his penpal protege what needed to be done to drain magic. The ponies demand to know who this was, and he admits that it was Cozy Glow.
At the school, Sandbar and the Crusaders see that Cozy has used the six magic relics from the Equestria races to create a sphere of concentrated magic, which Starlight is trapped in. Cozy admits she had to push Starlight in to get her out of the way and may need to do the same with Neighsay. She goes on to rant that she has learned that friendship is power, and by getting Twilight and her friends out of the way, and anypony else that may stop her, she will become the Empress of Friendship and cackles evilly.
Continued in "School Raze Part 2"
- Aesop Amnesia: Subverted. Twilight states that she's "finally" learned that it's okay to ask your friends for help, being set on them joining her in investigating Tirek from the start.
- Answer Cut:Fluttershy: Can't you just tell us your pen pal's name? I mean, since we're stuck here anyway?
Lord Tirek: Oh, why not? The irony is too perfect. Her name is...
Sandbar: Cozy Glow! I-I could've sworn I saw her come down this way when she left her office.
- Arson, Murder, and Jaywalking: Cozy Glow drains magic from Equestria, takes over the School of Friendship... and gives Smolder extra homework.
- Back for the Finale: Well, season finale anyway. After being absent for the second half of this season, Apple Bloom and Sweetie Belle finally return, the former having made a silent cameo in "Yakity-Sax".
- Basilisk and Cockatrice: Not only does a cockatrice appears as a creature imprisoned in Tartarus, but there's another caged creature resembling a basilisk.
- Batman Gambit: From Cozy Glow's stance, she had to expect that with the drain on magic, and her bringing up Tirek, that ultimately the Mane 6 would be assigned to check out Tartarus by the Princesses, drawing them away for her to continued unfettered. She had expected Starlight to go with them but was able to deal with that hiccup. Dealing with the interruption of Chancellor Neighsay, however, was an unforeseen snag, but that's when her being The Chessmaster comes into play (shown moreso in Part 2). How much Tirek himself played a role in planning the gambit is unclear.
- Big Bad Duumvirate: Cozy Glow and Tirek are working together.
- Bitch in Sheep's Clothing: Cozy Glow reveals that her cute and nice personality from all her previous appearances was just an act. She is the true Big Bad of the season and has manipulated events to drain magic from Equestria, trap the Mane Six in Tartarus, trap Starlight, and take over the School of Friendship so she can rule as the "Empress of Friendship".
- The Bus Came Back:
- Tirek appears in a major role for the first time since the season 4 finale (though he did have a brief cameo during the season 5 finale).
- Chancellor Neighsay also returns after being seen in "Friendship University".
- Cerberus returns after having been seen in the season 4 finale.
- Call-Back: The tunnels beneath the school are seen again, and are used by Cozy Glow to further her plans.
- Chair Reveal: Chancellor Neighsay is suddenly revealed sitting on the Headmare's chair when he swivels it around before Cozy Glow.
- Circling Monologue: While performing a full-on Evil Gloating with Starlight as audience, Cozy Glow moves in a wide loop around her and the magical circle, including the six artifacts, that imprisons the unicorn.
- Colliding Criminal Conspiracies: Cozy Glow drains the magic from all Equestria as a prelude to her coup of Twilight's school. Chancellor Neighsay uses the loss of magic as an opportunity to take over the school himself, which throws a wrench into Cozy's scheme.
- Continuity Nod:
- Yona is still afraid of heights.
- The events of "A Matter of Principals" are mentioned, with Spike stating that Starlight surviving Discord means she can survive anything.
- The scene where the Young Six ask to all be given extra homework plays out similarly to the scene in "The Hearth's Warming Club" when they all decide to stay at the school over the holiday break, just with Gallus and Smolder swapping roles.
- Pinkie Pie dresses up as a pizza-delivering pony (with a large pizza slice around her face) to try entering Tartarus, like she did in "Rock Solid Friendship".
- Twilight refers to the last time she went to Tartarus.
- Sapphire Shores is mentioned, with Cozy Glow giving one class tickets to one of her concerts.
- Among the inmates of Tartarus are a manticore, a cockatrice, a yeti, a bugbear, a chimera, a maulwurf and creatures from both Discord's realm and the "scariest cave in Equestria". Likewise, the flying arthropods bothering the main characters as they approach Tartarus are in fact flyders.
- The Coup: Cozy Glow stages a mostly nonviolent one to usurp not only control of the school, but Twilight's title as well, declaring herself Empress of Friendship. And given how insane she was, it's possible she was ultimately planning to usurp the other princesses as well to rule over all of Equestria.
- Darkest Hour: Equestria's magic is being drained and will be lost permanently in three days, the Mane Six and Spike are trapped in Tartarus, Chancellor Neighsay has taken over the School of Friendship and imprisoned the Student Six (except Sandbar), and Cozy Glow has trapped Starlight in a sphere of magic and crowned herself the Empress of Friendship.
- De-Power: All of Equestria is being drained of magic, which will happen in three days. Unicorn magic goes on the first day, magic from creatures in general on the second, and finally magical artifacts lose their power on the final day.
- Deus Exit Machina: Invoked. Cozy Glow intentionally doesn't tell the Mane Six that the key to Tartarus will break after one use, trapping them inside.
- Didn't See That Coming: Cozy Glow's plan to take control of the school didn't account for Twilight placing Starlight in charge, or Neighsay making an appearance.
- Didn't Think This Through: The Mane Six enter Tartarus without working on a plan to get out once the door is closed.
- Did You Just Punch Out Cthulhu?: Cozy Glow manages to trap Starlight, one of the most powerful unicorns in Equestria, in an energy bubble. Admittedly, Starlight didn't have her magic at the time (which was Cozy Glow's doing).
- Does Not Like Spam: According to Cozy Glow, Starlight "can't stand mustard".
- Emerging from the Shadows: Cozy does this as Starlight is trapped in a magic sphere and her true nature is revealed.
- Enfant Terrible: Think Diamond Tiara and Silver Spoon were bad? Cozy Glow has plans to take over Equestria. And she's a filly.
- Even Evil Has Standards:
- Despite his grudge against Twilight, Neighsay had come to the school to warn her about the magic drain (though he did assume the non-pony students were somehow behind it).
- Zigzagged with Tirek. Despite calling Cozy Glow's plan to drain all of Equestria's magic a "waste", he gladly told Cozy exactly how to do it, since it meant the ponies would suffer.
- Evil All Along: Cozy Glow exposes herself as not a flawed yet innocent filly, but as a Manipulative Bitch and a Chessmaster who wants power for the sake of power.
- Evil Cannot Comprehend Good: While not exactly evil, Neighsay is too eager to believe that Sandbar could turn on his friends so easily.
- Evil Gloating: Cozy Glow makes a full-on villain monologue to the imprisoned Starlight Glimmer, exposing her whole Evil Plan. Conveniently, Sandbar and the CMC are eavesdropping to her too.
- Evil Laugh: Cozy Glow does this to cap off the episode.
- Evil Mentor: Turns out Tirek has been this to Cozy Glow, having taught her how to perform her spell when she eagerly came to him asking for it. He even calls her his protege.
- Face Palm: Spike face-claws after Twilight claims "Nothing to worry about...", and then worriedly urges him to tell her that there's nothing to worry about.
- Fake Defector: Sandbar tells Neighsay that he was wrong to befriend the non-pony members of the young six. Cut to the next scene and he's gone to get Apple Bloom and the Crusaders for help.
- Fantastic Racism:
- When Smolder asks why Cozy Glow is in charge, Cozy responds that there's a difference between "scheming dragons" and ponies. It doubles as a Stealth Insult, as she's basically saying that ponies wouldn't be smart enough to figure out her plan.
- Neighsay's first order of business upon taking over as head of the school of friendship is to get rid of the non-pony students. In fact, he actually accuses them of being behind the magic drain after catching them.
- While studying, the Young Six spot Cozy Glow emerging from the hatch leading to the catacombs beneath the school. It is later revealed that this is where Cozy Glow has put together the spell to steal Equestria magic.
- Also, when the Young Six ask to be given extra homework so Smolder won't be the only one, Cozy Glow commends them on their loyalty and says Rainbow Dash would be proud of them. This later sets up how strong and closely knit the Young Six's friendship is, and how it will come into play the next episode.
- When the Mane Six confront Tirek, he refers to Twilight as the Princess of Friendship. Considering he was re-imprisoned immediately before Twilight was given that title, this was an early indicator that Tirek had been in contact with someone on the outside world.
- Cozy being evil was hinted at back in her very first appearance in "Marks for Effort", initially guessing Generosity and Magic as "Intelligence" and "Control", flashing a rather sinister face as she gets it, and not even bothering to drink the Empathy Cocoa Starlight gave her. She was also suspicious when the CMC offered to tutor her, and her biggest hint toward her true nature was when she said, "I guess I still have a lot to learn about friendship."
- Furry Reminder: Played with. Rarity complains about not being able to keep flies away with her magic so Twilight reminds her she can still swish them away with her tail, like real horses do. Rarity is appalled, as her tail is for decorative purposes.
- Gaslighting: When Smolder questions where Starlight is and why Cozy was left in charge so suddenly, Cozy brings up how Smolder seems to expect other species to act like "scheming dragons."
- God Save Us from the Queen!: Cozy Glow crowns herself the "Empress of Friendship" when she gets rid of Twilight.
- Good News, Bad News: Upon arriving to the doors of Tartarus, Twilight states that the good news is that they are still closed, meaning Tirek couldn't have escaped. As Applejack points out, this means there must be some bad news too. Which are that, without magic, they cannot enter.
- Hypocrite: Cozy Glow calls Smolder a "scheming dragon", yet it is revealed at the end of the episode that she has had her own scheme to take over Equestria in the works for quite some time.
- I Am Spartacus: When Cozy Glow passive-aggressively gives Smolder extra homework on the basis of questioning her, the other Young Six decide the rest of them deserve extra homework as well (though Gallus needs convincing before he joins).
- Immediate Self-Contradiction: Just before leaving for Tartarus, Twilight states that everything is going to be okay. She then grabs Spike and urges him to tell her everything's going to be okay.
- Interchangeable Antimatter Keys: A rare non-video-game example. The Key of Unfettered Entrance can unlock any door but breaks after a single use.
- Ironic Echo: Twilight thinks that Starlight's spell failed because she, Starlight, did her spell wrong. Starlight throws this back in Twilight's face after Twilight's own levitation spell fails shortly after.Starlight: [sarcastically] Maybe you did your spell wrong?
- Is the Answer to This Question "Yes"?: When Sandbar asks Apple Bloom if she's willing to help, she answers "Do mulberries have seeds?" Then she feels the need to come back to the window and points out "That's a yes."
- It Amused Me: Tirek claims that he answered all of Cozy Glow's questions about draining magic because he was "bored".
- It Only Works Once: Cozy Glow packs the Key of Unfettered Entrance for Twilight so she and her friends will be able to enter Tartarus, knowing the artifact will break as soon as it's used and strand them inside. Twilight uses the exact phrase when this happens.
- Just Between You and Me: Since they're trapped in Tartarus and can't tell anyone else, Tirek reveals Cozy Glow's duplicity to the Mane Six.
- Kissing the Ground: After being saved from a long fall by Gallus and Ocellus, Yona slumps down and kiss the earth, glad to be on safer ground than a cloud.
- The Magic Goes Away: What Cozy Glow's spell is doing: sucking all of Equestria's magic from the world and sending it into another dimension. If not stopped, in three days it will become irreversible.
- Mundane Utility: So mundane that it was never mentioned before, but apparently magic is normally used on prepared foods to keep them from rotting, meaning the ponies normally don't have to worry about air tight food containers. They soon find that without this magic their food goes bad quite rapidly.
- Nice to the Waiter: Invoked by Cozy Glow, as her plan is to be a Villain with Good Publicity. The start of the episode shows her being very helpful in general, even being nice to Derpy.
- Offscreen Moment of Awesome: We never see how Cozy Glow managed to trap Starlight in an energy bubble, though the following episode demonstrates that the magic-draining bubble has the ability to trap anyone trying to break the seal.
- Pet the Dog: While he does unjustly blame the student creatures for the loss of magic and locks them in a room, Neighsay does release them from the magical binding he put them in, and instead of intending to imprison them says he is simply going to get their guardians to bring them home.
- Properly Paranoid: Smolder suspects that Cozy Glow is up to something, and Gallus says that Cozy seems to be trying too hard to make others adore her. Turns out they are right.
- Reality Ensues: Despite Twilight considering Cozy Glow to be her "right-hoof pony", she doesn't place Cozy in charge of the school in her absence, as Cozy had hoped. No-one in their right mind would place a child in charge of a school, no matter how helpful that child is. When Cozy claims to Neighsay that Twilight did leave her in charge, Neighsay is rightfully disgusted, seeing it as all the reason he needs to take control of the school himself.
- The Reveal: Cozy Glow is revealed to be behind the disappearance of magic, working alongside Tirek.
- Rhetorical Question Blunder: Invoked when Sandbar asks Apple Bloom if she can help.Apple Bloom: Do mulberries have seeds? [beat] That's a yes.
- Shout-Out: Tirek's slurping noise is based on the "liver with some fava beans" scene in The Silence of the Lambs (which, considering how Tirek and Cozy Glow's relationship strongly mirrors that of Hannibal Lecter and Francis Dolarhyde, makes it more than fitting).
- Skeleton Key: The Key of Unfettered Entrance unlocks any door but breaks after being used.
- Spanner in the Works:
- Neighsay taking over the School of Friendship throws a temporary wrench into Cozy Glow's plans. However, she works around him, planning to trap him as she did Starlight.
- Sandbar being a Fake Defector allows him to free the rest of the Student Six after they're locked up by Neighsay.
- Stating the Simple Solution: When Rarity is having trouble with flies, Twilight tells her to use her tail to bat them away. Rarity shows offense, believing her tail is "decorative".
- Trailers Always Spoil: Cozy Glow's antagonistic role was given away by the next episode's summary.
- Watch Out for That Tree!: The episode opens with Derpy delivering mail to the school. The mailmare is just as clumsy as ever, smacking into the school's blazon because she was busy checking out the address on a letter.
- Wham Line:
- From Cozy Glow: "Enjoying yourself in there, Starlight? I'm sorry I had to lock you in, but what else could I do? You were going to ruin all my plans."
- Prior to the above, there's this from Tirek: "It seems my little protégé's plan worked after all."
- Widely Spaced Jail Bars: As usual, to not obstruct view the bars to Tirek's cage look wide enough to allow the centaur to walk in-between with little trouble. He even leans his entire torso through them at one point.
- You Answered Your Own Question: Pinkie Pie does this when she asks why the group should check on Tirek after Equestrian magic starts to fail.