Ponyville was a mess. Ponies were everywhere, moving bizarre and freaky objects of all kinds from place to place near their homes and shops while others called out advice and instructions. Pegasi flew through the air on constant patrol, keeping an eye on the numerous dark, heavy clouds scattered through the sky. A stranger to Equestria might wonder if the resident equines had lost their minds, setting false headstones right next to their front doors and stretching gossamer across their windows. However, not even Twilight Sparkle, Equestria's least socially-aware unicorn, was the least bit concerned by the activity. In fact, she was presently using her magic to hang a fake cow skeleton from a low branch of the Book and Branches Library while Spike and Owloysius plucked leaves off the tree according a carefully written plan Twilight had given them. Ponyville was a mess because Nightmare Night, a nocturnal celebration of all things spooky and scary, was approaching and everypony was hard at work decorating for it.

Everypony, that is, except for two. Lyra and Bon Bon were simply trotting down the street, looking at the decorations going up. A lidded cup with a straw floated in front of the mint-green unicorn as she took a few sips from it. "The pumpkin smoothies are pretty good this year," she said appreciatively, "are you sure you don't want to try some Bonny?"

"No thank you," the cream earth pony replied, "I'm going to be sick enough of eating pumpkin by the end of the season as it is. I don't need to hurry that along by drinking pumpkin too."

"Your loss," Lyra said before putting the straw back in her mouth. She sucked down the rest of her smoothie as the pair made their way to the Carousel Boutique. Bon Bon had commissioned a costume from Rarity and was heading there for a final fitting and to purchase the outfit. Lyra was accompanying her as an opinion source. They paused for a second to admire the boutique, which had been transformed from a bright and cheery merry-go-round to an old gothic tower with emaciated "guards" patrolling the top. "Wow," Lyra said simply, having not seen the new decorations before. Suddenly, the line of foam headstones with rubber zombie pony heads popping out of the ground that she'd arranged in front of her and Bon Bon's place seem cheesy.

"Jealous or something?" Bon Bon asked coyly, "You know nopony in town can beat Rarity when it comes to decorating for anything."

"That doesn't make it any less impressive," Lyra replied, walking to the boutique's door. Bon Bon was a step behind her as the unicorn opened the door and stepped inside, noting that the interior was virtually unchanged. Lyra found the contrast to be jarring, but she kept her opinion to herself as she sought out a trashcan for her empty cup.

"Velcome dahlings," a voice said from the back room, "Velcome to the Scare-usel Boo… ugh. No no, that simply will not do." From the back room stepped a white unicorn dressed in a black gown with flared red sleeves, a high collar, and with a matching black tiara in her mane, two blood-red ribbons woven through her purple mane, and a silver cross hanging from a thin chain around her neck. "Ah, Bon Bon," Rarity said with a smile, "you're just in time. Your costume is all set up and waiting for you. Right this way."

"You look great in that Rarity," Bon Bon said as she and Lyra followed the unicorn into the back room.

"Thank you," Rarity said, "It's not quite complete, but I'm saving the last few details for Nightmare Night itself. Now, behold." She stepped over to a curtain alcove and pulled the curtain aside to reveal Bon Bon's costume on a ponyquin. A purple-and-black flared skirt wrapped around the hips, leaving just enough flank exposed to show a cutie mark while a lighter purple vest trimmed in black adorned the chest. High black boots that looked like they were made of shiny black scales and a wide brimmed point black hat with a false cream-colored unicorn horn attached to the front completed the outfit. At Rarity's direction, Bon Bon got up on the display platform and held still while the unicorn transferred the costume onto her piece by piece. "And there we go," the fashionista declared as she settled the hat in place, "Bon Bon, you shall be the most fabulous witch to grace the world this year, if I do say so myself. How does it feel?"

"It feels perfect," Bon Bon said, moving around to test the outfit's fit. She looked at Lyra, struck a pose and asked, "so what do you think?"

"You look… good," Lyra said, moving to look at Bon Bon from several angles, "The horn's a nice touch. If I didn't know it was part of the costume, I'd swear you were a real unicorn." Bon Bon blushed as Rarity clopped her hooves in glee.

"Now," the white unicorn said, regaining her composure, "Just give me a few minutes to make some last-minute adjustments and you can take it home." While Rarity levitated over spools of thread, needles, and other tools and began to fuss over Bon Bon, Lyra went out to the main room to look around and wait. After a few minutes of admiring Rarity's latest creations – a combination of fall fashions and Nightmare Night costumes – the sound of the door opening and the bell ringing caught Lyra's attention. She looked over to see Twilight entering the boutique.

"Oh, hello Lyra," the lavender unicorn said in surprise, "what brings you here?"

"Bonny wanted my opinion on her costume," Lyra answered, tilting her head toward the back room, "Rarity's busy with her at the moment. How about you?"

"I've got a costume of my own to pick up," Twilight said. Lyra nodded as Twilight went to the back and knocked on the door.

"Just a minute," Rarity called. Twilight waited for a second and then turned away to find a place to sit.

"Do you have your costume yet Lyra?" Twilight asked.

"No," Lyra said slowly, averting her eyes away from the unicorn and the back room door, "I… won't be able to take part this year. The… it'll be 'that time' on the Night." Twilight's eyes went wide and her mouth opened in a silent "oh" of understanding.

"Have you…" Twilight started to ask, her gaze sliding toward the back room. Lyra shook her head firmly. "You should," Twilight said in a low voice, "I mean, she did move in with you just a few weeks ago."

"I know," Lyra muttered, digging at the floor with a hoof, "I just haven't been able to work up the nerve."

"The nerve for what Lyra?" The green unicorn's head shot up and spun toward the back room door, where Bon Bon was standing with an inquisitive look on her face.

"N-nothing," Lyra lied, starting to sweat, "you all done? Great. I, uh, just remembered I need to get some new strings. See you at home Bonny!" She rushed out the door as the cream-colored earth pony looked on in bewilderment.

"You just got new strings two days ago," Bon Bon said quietly.

A couple of days later, on the eve of Nightmare Night, Lyra's odd behavior had been forgotten and life in the pair's home returned to normal. At least, as normal as life could get just prior to Nightmare Night in a house occupied by a pair of mares who were considered a couple by everypony except themselves. Bon Bon continued to insist that she'd agreed to move in to Lyra's place only to save on rent and devote more bits toward expanding her candy store. For her part, Lyra simply declined to comment beyond saying it was nice to have another pony to while away the evenings with. At the present time, the pair were lounging on Lyra's couch, listening to a Nightmare-themed music record. The mint-green unicorn was holding her namesake instrument in the crook of one leg as she strummed it in a lazy attempt to fit its sound in with the music. "I don't think it's going to work Lyra," Bon Bon said after a while.

"Yeah," Lyra said with a sigh, giving the instrument one last hard strum before setting it aside, "It's not easy to get spooky tones out of-" A sudden shiver went through her and her eyes went wide in shock.

"You ok?" Bon Bon asked.

"Yeah," Lyra said lamely as she slid off the couch, "Just a sudden unexplainable chill. I'll be right back." Bon Bon frowned slightly as the unicorn trotted into the kitchen and disappeared from sight. She heard the refrigerator open followed by the sound of bottles and food being shoved around. "Bon Bon?" Lyra called out, "You haven't seen a small bottle of green liquid around, have you?"

"You mean the cloudy-looking one in the back?" the earth pony asked, getting off the couch to join her friend.

"Yes." Lyra's voice was laced with the beginnings of panic.

Bon Bon hesitated before resuming her approach at a slower rate. "I… may have thrown it out," she said.

"What?" Lyra's poked her head into view, her face frozen in an expression of fear and disbelief.

"It… smelled like it had gone bad," Bon Bon said, backing away now as she realized she'd broken some unspoken rule.

Lyra's jaw moved soundlessly for several seconds. "Of course it smelt bad," she shouted, "Zecora's potions aren't… argh!" She collapsed to the ground, front hooves pressed to her head. "Stay back!" she yelled as Bon Bon started to run to her side, "Rrrrrgh… Too early…" She struggled to her feet, cast a pained glance at Bon Bon, and then bolted past her and up the stairs to her bedroom.

"Lyra!" Bon Bon cried, chasing after her, "What's wrong? What's happening?" Lyra ran into her room, slamming the door shut behind her and locking it. When Bon Bon reached the door, she heard the sound of furniture being shoved around, accompanied by grunts of pain and whimpering. A thud indicated something heavy being shoved up against the door, and then the only sound was a whimper that slowly grew into short, blood-curdling scream. "Lyra!" Bon Bon screamed in response, pounding at the door. After a minute or so, she stopped and took a few deep breaths to clear her head. She then ran to her own room and dug the small key for the interior door locks out of her dresser. She galloped back to Lyra's door and unlocked it. Then she applied all the strength her earth pony heritage provided her in forcing the door, and the bed that had been pushed up against it, to move aside and let her peek into the room. A mint green figure lay huddled in the center of the floor, shaking with what seemed to be anguish. Bon Bon shoved the door open a little more and slipped into the room. "L-lyra?" she asked, approaching the figure with caution, "What's wrong? Come on, talk to me." Lyra's head shot up suddenly, and Bon Bon shrieked as she tried to back away from the sight.

It was Lyra, only not. Her coat had grown out and become ragged, her mane was almost nonexistent. The creature growled as it stood up, revealing sharp fangs as it stared at the cream earth pony with maddened yellow eyes. In place of hooves, it had paws with dangerous-looking claws that dig into the floor as it knelt to pounce. Bon Bon screamed and threw herself flat as the creature leaped over her and squeezed through the door. Bon Bon's heart raced as she lay panting on the floor, mind spinning in circles as she tried to comprehend what she had just seen. A horrible sound, like a cross between a whinny and a howl, broke her out of her stupor and drove her to her feet. "Lyra!" she shouted as she spun toward the bedroom door and took off in pursuit of whatever her friend had become.

The whinny-howl carried through the town, causing many ponies to pause in the darkening streets and look around in confusion and fright. Inside Books and Branches, a pair of lavender ears shot straight up, followed by the head they were attached to looking up from the book it was buried in and turn toward the nearby window. Twilight felt her mouth start to go dry as she saw the full moon hanging among the stars and she leaped off her bed and galloped downstairs. "It's a day early," she muttered, and then called out, "Spike! I have to go to Zecora's! Lock everything and don't let anything but Owloysius inside until I get back!"

"Ok," Spike said, scratching his head as he watched Twilight leave the library. He cast a glance at the owl perched on a nearby desk. "You're already here," he said, "so… I wonder what's going on?"

"Hoo." Owloysius shrugged his wings.

"Thanks so much for helping Rarity!" Pinkie Pie exclaimed happily.

"You're quite welcome dear," Rarity said, backing out of Sugar Cube Corner so she could keep an eye on the pink earth pony and prevent anything else from being added to her already bulging saddlebags, "but are you sure you don't need all these… lovely baked goods for the party tomorrow?"

"Nope," Pinkie declared, "The Cakes and I are going be spending all day tomorrow baking for the party. These are just to say thank you for helping me decorate!" She moved to stuff another cupcake into the left-side bag when a strange half-whinny, half-howl caused both her and Rarity to stop and look in the direction of the source. "What was that?"

Rarity's reply was drowned out by screams and pounding hooves as ponies stampeded in the general direction of away from the sound. "The horror, the horror!" Roseluck yelled as she passed by. Rarity raised an eyebrow at the retreating figure before turning to see what had set the excitable filly off this time. Her other eyebrow shot up as she saw a mint-green, pony-esque creature bounding down the street, aiming for a foal who was paralyzed with fear.

"Oh no you don't you… whatever you are," Rarity said coldly as she wrapped the creature in her magic and tugged as it leaped into the air, using its own momentum to carry it over the foal and send it sprawling on the ground.

"Hey," Pinkie said, pointing at the thing, "Lyra's a marewolf!"

"A what?" Rarity asked.

"Marewolf," Pinkie answered, "you know, half mare, half wolf."

"How you know these things…" Rarity mused, shaking her head slowly. She turned her attention back to the creature just in time to see it pouncing toward her. With a shriek, she reared back and threw her front legs out to meet the pounce and the pair went rolling across the ground, ending up with Rarity on her back and pinned by the marewolf. "Help!" Rarity called, using her hooves and magic to keep the creature's teeth away from her. She looked over at Pinkie Pie to see the party pony munching on some popcorn she'd gotten from somewhere. "Pinkie Pie! What are you doing?"

"Don't worry," Pinkie said calmly, "Bon Bon's got your back." Rarity only had enough time to say "huh?" before a cream colored blur knocked the marewolf off of her. She rolled to her feet to see Bon Bon and the mint-green beast staring each other down. Bon Bon had tears in her eyes.

"Lyra," she sobbed, "What's happened to you? Please, tell me you're still in there somewhere." A low growl rumbled in Lyra's throat as she took one threatening step forward. Bon Bon held her ground and kept her gaze on Lyra with a pleading look in her eyes. "Lyra, please talk to me. Say something." She took a few steps and Lyra crouched down with a dangerous growl, every muscle tensed. Bon Bon hesitated, but then crossed the remaining distance between her and the marewolf. "Come on Lyra," she said, reaching out a hoof, "You… you mentioned Zecora earlier. Maybe-" Lyra cut her off by poucning, knocking Bon Bon to the ground and pinning her. "Please Lyra," the earth pony whispered, "you don't have to do this. Let me help you." Lyra bared her fangs and raised her head slightly. "Please," BonBon begged, "I… I love you." The marewolf seemed to hesitate, but then her mouth opened and her head shot down toward Bon Bon's throat. Bon Bon closed her eyes and braced herself, but the killing bite never landed. She heard the sound of a small impact and felt the pressure lift off her shoulders as the marewolf staggered and collapsed to the ground next to her. She looked up to see Zecora and Twilight Sparkle running down the street toward her. The zebra had a short wooden tube in her mouth, which she flipped out onto her back with a practiced toss as she neared.

"Good shot Zecora," Twilight said, "I was afraid we weren't going to make it in time." She went to Bon Bon and helped the mare to her feet while Zecora bent her head down and plucked a dart from Lyra's neck.

"What did you do to her?" Bon Bon asked hysterically, glaring at the zebra standing over the unmoving body of her friend.

"Calm yourself, there is no need to weep," Zecora said with a small smile, "The dart contained only a sedative to make her sleep."

Bon Bon blinked and then looked down at Lyra. The mint-green creature's chest was rising and falling gently. "What…" Bon Bon's voice caught in her throat, "What happened to her?"

"She's a marewolf," Pinkie Pie declared as she and Rarity came over to the group, "It's definitely the best Nightmare Night costume I've ever seen."

"It's not a costume Pinkie," Twilight said, giving the pink pony a sideways glance, "She's a genuine marewolf. The light of the full moon makes her transform into this. She can normally control herself when she changes thanks to a potion Zecora mixes up for her, but I guess she was caught off guard by the full moon coming a day early this month."

Bon Bon's head hung low and tears started to fall from her eyes. "A-actually," she stammered, "It's my fault… I… I t-threw the potion out." She glanced up to see the shocked looks on Twilight and Zecora's faces. "I-I didn't know what it was," she squeaked, "I did th-the shopping a few days ago and… found the potion while I was stocking the fridge. I-it s-smelled horrible, so I thought it had… whatever it was had gone bad, so I… I…" She collapsed to the ground, sobbing hysterically. Pinkie and Rarity raced to give the poor mare a hug and a shoulder to cry on.

Twilight sighed and shook her head. "I told Lyra she needed to tell you about this," she said. Rarity shot the unicorn a dirty look.

Bon Bon spent several minutes crying herself out, and then looked up at Twilight. "How long?" she asked.

"How long has she been a Marewolf?" Twilight asked. When Bon Bon nodded, she answered, "Just a few months actually. Remember when her trip to Hoofington?"

"Yes," Bon Bon said, "She'd gone to audition for something and to visit family. She… was a few days late coming back. She told me she'd gotten a call-back…"

"A tale told to way-lay fear," Zecora said, "but now the real story you should hear. Her journey there was as unremarkable as can be, but on her return she took a road near the Everfree. She and I met by a whim of fate, and that proved to be a lucky break. Not long after, we were attacked by a foe whose true nature I did not immediately know. I thought it to be a wolf with a coat of peculiar tan, but as we later learned, it was actually a Lycan."

"Lycans are a very rare kind of monster," Twilight cut in, "Their bite can turn ponies into marewolves. Zecroa was able to drive the Lycan off, but not before Lyra was bitten on the shoulder."

"I took her to my home to treat the bite," Zecora said, picking up the story, "to be sure it healed, I had her stay for the night. That decision proved doubly wise, for that night was marked by the full moon's rise. With herbs and potions I kept her subdued, but since she transformed, there was nothing more I could do, for the curse is permanent after the first full moon."

"But, there's that potion," Bon Bon said, hope returning to her face, "do you have some with Zecora? If we give it to her before she wakes up, everything will be ok, right?"

Twilight shook her head. "She has to take the potion before she transforms or it won't have any effect," she said, "All we can do now is keep her sedated or locked up until morning when she changes back."

"Fine," Bon Bon said, starting to dig her head under Lyra's body, "I'll take care of her. It's the least I can do. Where's the sedative?" The limp marewolf suddenly levitated off the ground as Twilight wrapped her in telekinetic magic.

"Let's put her in my basement," the lavender unicorn said, settling Lyra on Bon Bon's back, "The door and lock are strong enough to keep her contained, and we'll all be able to get some sleep." She gestured for Bon Bon to follow her and began walking toward the library.

"I must return to start a fresh brew," Zecora said, "Hopefully there won't be any herbs I'll need to accrue." As the zebra turned and trotted away, Bon Bon glanced back at Lyra and then followed Twilight.

"Twilight," she asked as the pair neared the tree, "How is it that you knew about Lyra?"

Twilight gave an embarrassed chuckle. "I just happened to go visit Zecora the day after and walked in on her explaining the maintenance potion to Lyra," she said, "It became my task to make sure Lyra was coping and that she was paying attention to the lunar cycle." She frowned and glared up at the moon and added, "Part of me wants to demand an explanation from Princess Luna for why the full moon was a day early, but it might just have been a clerical error or something." She looked back down with a sigh and knocked on the library door, calling out "Spike! It's me. Open up!" She was rewarded by a click and the opening of the door, but the head that peeked out around the door didn't belong to a baby dragon.

"Hoo," Owloysius said in welcome.

"Thanks Owloysius," Twilight said as she and Bon Bon entered the library. The owl took one look at the cream earth pony's load and flew back to his perch to await further instructions. "This way," Twilight said, leading Bon Bon over to a door situated under the stair case. As the pair stepped through and descended into the basement, Lyra began to stir. "Quick!" Twilight yelled, lifting the marewolf off Bon Bon's back and setting her on the stairs, "Let's go." The unicorn and earth pony galloped up out of the basement and shut the door behind them, Twilight setting the lock in place and reinforcing it with magic before dropping to her haunches and breathing a sigh of relief. "Ok," she said, "Everything should be fine now Bon Bon. You should go home and get some sleep."

Bon Bon shook her head. "No," she said firmly, sitting down next to the door, "I'm going to stay here and guard her. I want to be there the moment she changes back."

Twilight opened her mouth to protest, but then broke under the intensity of Bon Bon's look. "Fine," she said, "I'll go get you a blanket."

A tentative knocking woke Bon Bon from slumber. She blinked and looked around in confusion, not recognizing her surroundings for a moment. Sunlight streamed in through a few windows, bathing the library in golden warmth. There was another knock, followed by a voice, "H-hello? Anypony?" Bon Bon sprang to her hooves as the events of the previous night returned to her memory. She nearly tore the basement door out of its frame before remembering to undo the lock, and then cracked the door open cautiously and peeked inside.

"Bon Bon?" Lyra asked, eyes squinting in the sudden light. The mint green unicorn was back to normal. Her coat was still disheveled, but she had hooves, a full mane, and normal-looking eyes.

"Lyra!" Bon Bon cried, flinging the door open and grabbing Lyra up in a hug, "Oh thank Celestia, you're ok!" Lyra returned the hug and the two stood like that, leaning o neach other for several seconds. Finally though, Bon Bon pulled away and averted her gaze. "Lyra," she said, "I'm sorry. I should have asked you about that potion before doing anything with it."

"No," Lyra said, stepping forward to hug Bon Bon again, "I should have told you. I mean, I let you move in with me after all. I knew you'd find out sooner or later." She sniffed sadly. "I just wish you didn't have to find out this way."

"Well, I know now," Bon Bon said, pulling away again but keeping her hooves on Lyra's shoulders, "Zecora's making a fresh potion, and you didn't hurt anypony last night, so we can move on and deal with this together." Lyra gave her a grateful smile. "Just promise me, no more secrets, ok?"

"No more secrets," Lyra agreed. The pair hugged again, taking comfort in each other's presence.

"Ugh," a voice said from above, "get a room you two." Lyra and Bon Bon looked up to see Spike looking down at them from the stairs with a look of disgust on his face. The couple shared a glance and a smirk and separated.

"Breakfast?" Bon Bon asked.

"Sugar Cube Corner," Lyra answered. They turned and walked toward the door side-by-side. "By the way," Lyra said just before they got outside, "Last night, just before I got knocked out, I think you said something." Bon Bon blushed and avoided Lyra's gaze, and the unicorn smirked slightly before leaning in close and whispering, "I love you too Bonny."