Fluttershy and Zecora visit a swamp to gather supplies for Fluttershy's animal sanctuary. After Zecora slips and falls in the water, a flower on a lily pad emits a burst of pollen that causes her to break out in a red rash. By the time Fluttershy gets her back to Ponyville to see a doctor, she has started coughing up bubbles. The doctor diagnoses her with swamp fever, a disease that has no known cure and that eventually causes its victims to turn into trees. Fluttershy resolves to find a cure and save Zecora, believing that the legends of a healer known as the "Mystical Mask" must be true.
She drafts Twilight Sparkle to help research the legends, but they come up with nothing after several hours in Twilight's library. Twilight goes to bed while Fluttershy keeps working all night; the next morning, a fatigued Fluttershy wakes Twilight with her conclusion. The Mystical Mask was Mage Meadowbrook, who lived in Hayseed Swamp long ago. The two immediately set out for the old village and find it deserted except for Meadowbrook's descendant Cattail, who has kept an eye on her old house. In one of her old journals, Fluttershy finds her experience with a swamp fever epidemic. Seeing that flash bees were immune to the disease, she determined that their honey could provide a cure, but the bees proved highly aggressive in defending their territory. The journal ends with Meadowbrook successfully curing the epidemic, but gives no details of how she finally got the honey.
Fluttershy discovers that she too has contracted swamp fever, but pushes on despite her exhaustion to try and get the flash bees' honey. Cattail leads her to the hive, but her attempts to talk to the bees provoke them to sting her repeatedly and she passes out from pain and sleep deprivation. She wakes up three days later in Meadowbrook's old bed, and Cattail tells her that Zecora has started to sprout leaves and explains that he and Twilight have tried and failed to get the honey. As Fluttershy starts to despair, she notices a bee nuzzling up against one of Meadowbrook's old masks and suddenly realizes what she did. The stripes on the mask resemble the markings on the queen bee, around whom all the males become docile. When Fluttershy returns to the hive and dons the mask, the males leave her alone and she is able to retrieve the honey.
Both Fluttershy and Zecora make a full recovery, and Zecora thanks Fluttershy for all the trouble she went to in order to find a cure. Fluttershy admits that she might have succeeded sooner if she had taken better care of herself along the way. They are interrupted by the arrival of the doctor who diagnosed Zecora, asking if they have found a cure yet — because now he has swamp fever.
- Accidental Misnaming: Fluttershy calls Cattail "Dogtail" due to being completely out of it after not having slept for days.
- Accidental Rhyme: Fluttershy finds Zecora's speaking pattern is a bit contagious.Fluttershy: Gee, I don't know. It's a pretty big pack. So maybe enough to fill up this sack? [gasps, laughs] Oh, my! You're rubbing off on me, Zecora!
- Alchemy Is Magic: Meadowbrook was an earth pony, and thus couldn't use the flashier and more direct kind of magic usually seen on the show. Instead, she specialized in brewing cures and potions, which was evidently sufficient to earn her the appellation of "sorceress" and "mage".
- An Aesop: If you don't take care of yourself, you won't be able to take care of others, either.
- Arboreal Abode: The home where Meadowbrook and her mother lived, and where Cattail seems to live today, is inside of a hollow tree.
- Artistic License Biology: The Flash Bees featured in the episode consist of aggressive males who sting intruders to protect the queen bee. In real life, only female bees (workers) have stingers, and the only duty the males (drones) have is to mate with the queen. Real bees also communicate through scent as much as by sight, and so should not be fooled by a mask without an appropriate scent. Of course, in real life, bees also have no electric powers, so these might just be other characteristics of the species.
- Asleep for Days: Fluttershy pushes herself so hard throughout the episode, she faints after being attacked by a swarm of Flash Bees. She wakes up three days later.
- The Atoner: Fluttershy blames herself for Zecora's illness, and she's searching for the cure as a way to make up for it.
- Baleful Polymorph: As it runs its course, Swamp Fever causes its victims to spout leaves and branches and eventually transform into trees.
- Body Horror: Slowly being transformed into a tree, starting with twigs and leaves growing out of your skin. The doctor's book shows further stages of the transformation, including one of a very sad looking, nearly leafless tree with four tall roots.
- Chekhov's Gun: Meadowbrook's healer's mask turns out to be the key to getting the Flash Bee honey, as it makes the Flash Bees see the wearer as one of them.
- Continuity Nod:
- Mage Meadowbrook was briefly mentioned as the alleged previous owner of Starlight Glimmer's Staff of Sameness in "The Cutie Map". Meadowbrook's legacy plays a critical role in finding the cure to Swamp Fever.
- Twilight states "Anypony who lives in a tree is okay by me!" Twilight herself used to live in a library made out of a tree, until it was destroyed by Tirek.
- Fluttershy's research skills may be a nod to "Magic Duel". Fluttershy was the one who found the book detailing the Alicorn Amulet's powers.
- Cooking Duel: When Fluttershy first finds Twilight, she and Spike are having a bake-off.
- Culture Chop Suey: Meadowbrook's culture is a portmanteau of different ones, including South American, Mayincatec, Haitian, and surprisingly, Cajun.
- Darker and Edgier: For starters, Zecora and Fluttershy spend the length of the episode afflicted with a fatal disease that, as far as they know, doesn't have a cure.
- A Day in the Limelight: Zecora rarely appears for longer than a single scene in any given episode, and the last time she had a large role was back in Season 3.
- Deconstructed. Fluttershy vows to literally never rest until she has cured Zecora of her Swamp Fever, since she feels responsible for her condition. This includes staying up all night researching, followed by immediately flying off to a faraway location, and taking action while she's come down with Swamp Fever, all without taking a break. Eventually she ends up rushing into a confrontation with a swarm of vicious bees she can neither talk nor Stare her way out of, and she falls asleep for three days, wasting precious time as Zecora's condition worsens.
- Mage Meadowbrook is a more positive example. It's her perseverance and determination to find a cure that allows her to finally be able to heal the sick townsfolk of swamp fever.
- Diary: Mage Meadowbrook's entire library consists of personal journals, which include griping about yucky peas as a foal and a possible Puppy Love story as a young filly.Twilight: [reading from Meadowbrook's journal] "I met a colt today. He pulled my mane, so I put a frog on his head." Also not helpful, but I do kinda wanna see where it goes!
- Door Dumb: A sleep-deprived Fluttershy arrives at Meadowbrook's house and tries to push open the door — to no avail. She declares their only option is to dig their way in! Twilight turns the doorknob.
- Dramatic Thunder: Doctor Horse's announcement that Zecora has swamp fever is accompanied by lots of reverb and dramatic lightning — even though they are indoors.
- Dressing as the Enemy: Fluttershy and, previously, Meadowbrook, managed to get the honey by wearing a mask that resembles the Queen Bee's color patterns, so they don't get attacked by the swarm.
- Early-Bird Cameo: Meadowbrook and Cattail were first introduced in Issue 58 of the comics. Meadowbrook was first mentioned back in "The Cutie Map".
- "Eureka!" Moment: When she hears Cattail mention disguises, and sees a bee nuzzling Meadowbrook's mask, Fluttershy realizes she can use the mask to approach the hive without provoking the bees.
- Exhausted Eye Bags: Fluttershy sports these throughout most of the episode, due to refusing to sleep until she finds the cure for Swamp Fever to save Zecora.
- Eye Cam: The shot being framed by an eyelid slowly opening happens twice:
- First in the flashback, when Meadowbrook's mother open her eyes to see her daughter bringing her the cure.
- Then when Fluttershy wakes up after sleeping for three days, to see worried faces of Twilight Sparkle and Cattail.
- Fainting: After refusing to get any rest for days, Fluttershy finally faints from exhaustion after failing to retrieve the honey from the Flash Bees.
- Famous Ancestor: Cattail may appear just like any other pony, but he's actually one of Mage Meadowbrook's descendants.
- Fate Worse than Death: The final fate of those who suffer from Swamp Fever; they turn into the very kind of tree that produces the flowers that infect ponies in the first place, essentially becoming a living plague factory.
- Find the Cure!: The doctor says that there is no known cure for Swamp Fever, but Zecora and Fluttershy both remember a tale of a healer who could cure any disease. Fluttershy works herself sick through the rest of the episode finding the cure.
- The Friends Who Never Hang: This is the first time that Fluttershy and Zecora share the spotlight for a significant part of an episode.
- Ghost Town: Hayseed Swamp is one now, but apparently it was a thriving town back in Meadowbrook's time.
- Gone Horribly Right: Fluttershy's hard-learned assertiveness backfires on her in this episode; She absolutely refuses to let Twilight talk her out of going on the journey to Meadowbrook's village, or going ofter the Flash Bee honey when she gets sick... which ends up almost costing her dearly.
- Got Me Doing It: After spending time with Zecora, Fluttershy starts speaking in rhyme as well.
- Here We Go Again!: The episode ends with Dr. Horse asking if Fluttershy has found the cure, because he's contracted swamp fever as well.
- Heroic RRoD: Fluttershy just keeps pushing to find a cure for Zecora, ignoring her own sleep deprivation and sickness—until she collapses and has to sleep for three days.
- Hidden Depths: When Fluttershy puts her mind to it, her researching skills are very impressive.
Fluttershy: Are... are you cooking?
- When Fluttershy arrives at the castle, Twilight is enjoying cooking with Spike, much to her surprise. Even more surprising, Twilight wins the contest because Spike ate all of her muffins.
- I Have Many Names: It turns out that the Mystical Mask that both Zecora and Fluttershy have heard about in stories is actually Mage Meadowbrook, an ancient sorceress well-known throughout Equestria.
- Insect Gender-Bender: As explicitly stated in the episode, the majority of the flash bees are male, with the sole exception of the queen. This is in contrast to how, in real life, the workers of the hive are all genetically female — the male drones exist solely to mate with the queen, and do not even have stingers.
- Insect Queen: The flash bee hive seems to be ruled by a queen that is visibly larger than the male workers. While the queen is not seen commanding or ordering the other bees about, she is shown wearing a crown, as well as standing on a raised, throne-like dais in the center of the hive.
- Insomnia Episode: Fluttershy refuses to sleep until she's found the cure for swamp fever, no matter how tired she feels. She eventually falls asleep at the worst possible time, when the flash bees are attacking her.
- Iris Out: Like many episodes, this one ends with a black iris slowly closing. In this case, around a sick Doctor Horse — who's sneezing from the swamp fever, and some lightning is seen going through the iris and into the black part of the screen.
- It's All My Fault: Fluttershy feels this way about Zecora getting sick, since it happened while Zecora was helping her gather supplies.
- Laser-Guided Karma: The doctor immediately disappears after his diagnosis, without even bothering to offer Zecora any consolation or help in any way. At the end of the episode, it's revealed that he's caught Swamp Fever himself and is almost turning into a tree by the time he arrives at Zecora's hut.
- Magic Antidote: The flash bees' honey immediately cures Swamp Fever and reverses its symptoms regardless of how far it's progressed.
- Meaningful Name: The Crisscross Moss Zecora and Fluttershy gather has criss-cross patterns all over it.
- Messy Hair: Fluttershy's mane becomes increasingly disarrayed and discolored as she works herself closer and closer to exhaustion, and begins to exhibit symptoms of the very illness she's seeking a cure for.
- Motor Mouth: Fluttershy engages in this while explaining things to Twilight.Fluttershy: Zecora-has-Swamp-Fever-and-there's-no-cure-and-it's-all-my-fault-and-the-only-pony-who-can-cure-it-is-the-Mystical-Mask-and-I-need-your-help-to-find-her!
- Mouth Cam: Right after the opening credits, we gets a shot from the inside of Zecora's mouth, framed by her teeth, as the doctor examines her palate.
- Mythology Gag: Meadowbrook is both the name of a G3 pony and one of the potential names Lauren Faust considered giving Fluttershy.
- No-Sell: The Flash Bees are unaffected by Fluttershy's Stare, though whether or not that's due to her declining health is unknown. According to Twilight, her magic is also ineffective against them.
- Noodle Implements: While Fluttershy slept, Twilight and Cattail tried some other ways to get honey from the Flash Bees, including some ways that Cattail "won't even speak of." Just thinking about them makes him shiver in horror.
- OOC Is Serious Business: Fluttershy knows Zecora is getting worse when she stops speaking in rhyme.
- Ooh, Me Accent's Slipping: A rather subtle instance. When Fluttershy visits a bedridden Zecora, she speaks with Brenda Crichlow's normal speaking voice, but when she attempts to make a rhyme, she goes back to her pseudo-African accent.
- Overworked Sleep: Fluttershy becomes so tired from Swamp Fever and her attempts to find its cure that she collapses. When she wakes up, Twilight and Cattail tell her she was asleep for three days.
- Plague Doctor: The birdlike masks worn in the episode are reminiscent of the beaked masks won by historical plague doctors to avoid contracting the Black Death. The similarity is further accentuated by Fluttershy and Meadowbrook wearing them while trying to find a cure for a dangerous, difficult-to-eradicate sickness.
- Polka-Dot Disease: The most obvious outward symptom of Swamp Fever is orange spots appearing all over the afflicted equine's body. It takes a more disturbing turn when leaves and branches start sprouting from these spots.
- Poor Communication Kills: Twice over, in Meadowbrook's case. She made notes about every part of her experience with swamp fever except for how she got the Flash Bees' honey, which would have saved Fluttershy a lot of grief. Also, she apparently never bothered to share her findings with anypony else, severely limiting other independent efforts to find a cure.
- Present Absence: While Meadowbrook may have disappeared without a trace in the past, her legacy (her journals, specifically) drives the plot and allows Fluttershy to save Zecora and herself.
- Pun-Based Title: The title is a pun on the phrase "a wealth of information."
- Retcon: Mage Meadowbrook being an earth pony overwrites Twilight claim of her being an "Eastern unicorn", back in "The Cutie Map", though it's justified since Meadowbrook is so Shrouded in Myth there is plenty of In-Universe disputation on her feats to the point Twilight and Fluttershy have to connect various separate stories together to get the full picture of who she was and where she lived.
- Rhymes on a Dime: Obviously for Zecora, but Fluttershy starts picking up on this habit. And when Zecora is as sick as she gets, she actually falters on her rhyming.
- Scary Stinging Swarm: In order to get the cure for Swamp Fever, both Fluttershy and Meadowbrook have to contend with a swarm of aggressive flash bees, which vigorously defend their nest and honey and attempt to sting and electrocute anybody who approaches them.
- Shock and Awe: The Flash Bees have the ability to naturally generate electricity. Their swarms are visibly cracking with lightning, and they can charge their stings with electricity to add an extra painful jolt to their attacks.
- Shown Their Work:
- Swamp Fever is another name for not one but two real diseases: equine infectious anaemia and malaria.
- Meadowbrook's bird-shaped healer's mask is reminiscent of those worn by real-life plague doctors, which helped filter out airborne diseases.
- Sick Episode: The whole episode revolves around Zecora getting sick with swamp fever, and Fluttershy in the role of the caregiver. Unlike previous such episodes, this one disease is quite nasty in that it can prove fatal, it has no known cure, and is quite contagious. Even Fluttershy herself gets sick.
- Single Line of Descent: Surprisingly averted for a kid's show. Fluttershy refers to Cattail as "one of Meadowbrook's descendants", implying there are more than just one, as it would happen in real life.
- Skewed Priorities: Just before they head out on their quest, Twilight points out that they should pack some food. Fluttershy states that she packed some of the cauliflower bites that Spike made. Twilight is briefly crestfallen that none of her own sweet potato muffins made it into the bag (Spike liked them so much, he ate the whole batch).
- Sleep Aesop: When Fluttershy loses sleep trying to help Zecora, Twilight tries to convince her to sleep, but she doesn't, which leads to Fluttershy getting swamp fever.
- Sleep Mask: Who'd have guessed Spike sleeps wearing a mask, just like Rarity?
- Sneeze of Doom: An advanced symptom of the swamp fever is the patient sneezing small lightning bolts. The first time Zecora sneezes this way, it singes Twilight's mane.
- So Much for Stealth: The flash bees don't pay attention to Meadowbrook peeping inside their hive at first... until she breaks a twig of the tree under her hoof. Then they immediately attack.
- Stating the Simple Solution: When it seems like they can't get into Meadowbrook's former home, Fluttershy suggests digging their way in. Twilight points out that they could just try the handle, which the sleep-deprived Fluttershy failed to notice.
- Stealth Pun: The flash bees have electric powers, so the name isn't too surprising. They are, however, also bees animated in Flash...
- Subverted Rhyme Every Occasion: Zecora's failed attempts at rhyming.Zecora: That's marvelous, Fluttershy,
I am quite impressed,
While you're gone on your journey,
I'll try not to be... worried.note
- Swamps Are Evil: The potentially deadly Swamp Fever Tree seems to grow exclusively in swamps, and both swamps in the episode — the one near the Everfree Forest and the Hayseed Swamp — contain large groves of the dangerous trees. In addition, the Hayseed Swamp is also home to swarms of the aggressive, highly territorial and electrogenic Flash Bees.
- Talking in Your Sleep: When Fluttershy gets some info on Mystical Mask, she goes to wake Twilight, and finds Twi dreaming about cooking utensils.Twilight Sparkle: [snoring] 9-by-13-inch pan...
Twilight Sparkle: [awake] Nonstick pans!
- Transflormation: The final stage of Swamp Fever ultimately sees its victim transform into a tree.
- Verbal Ticked: As Zecora gets sicker, her rhyming skills fail, which alerts Fluttershy that this is really serious.
- Viral Transformation: In the final stage of Swamp Fever, not only does the pony turn into a tree, but the tree they become has flowers that spread the disease to more ponies. Even before this happens, it is possible to catch the disease through normal airborne contagion.
- Waking Non Sequitur: Twilight blurts out "Nonstick pans!" when Fluttershy wakes her up.
- Witch Doctor: Mage Meadowbrook is one, and just like Zecora her tree is filled with witch doctor-like masks.
- Worf Had the Flu: Fluttershy meets an animal that she can't Stare into submission... but she's feverish and sleep-deprived at the time, so it's possible her Stare isn't at full strength.
- Worldbuilding: The bayou village in Hayseed Swamp where Meadowbrook used to live.