It had been a year since they moved into Ponyville. Sunny and Scootaloo loved being family, and while Hedera had caused panic at first. Once they proved that Sunny had it tamed, they slowly accepted it. Plus finding out that Pipp, Zipp, and Sunny used to live in the Everfree, caused them to give Zecora a chance as well.
Now however, it was about to be the thousandth sun celebration, and Pipp and Zipp, had hid Sunny, Scootaloo, Apple Bloom, and Sweetie Bell in the basement of the Golden Oaks Library, and magically sealed the room to prevent them from getting caught by Nightmare Moon, who had broken free.
Everyone had felt Celestia's power surge as she fought Nightmare Moon, however she was out of practice fighting and had fallen, now trapped within the sun itself. Now Pipp and Zipp were back in their Cadence and Luna forms, and were now fighting her themselves at the castle, they used to call home.
Of course, all four of the crusaders wanted to help. And weren't going to let a little thing like a magical barrier stop them. They had left a stockpile of things to help fight Nightmare Moon hidden in the Castle Library. On top of that, Sunny had recently discovered she was the Alicorn of Lore, and while they were experimenting the crusaders found Sunny could open a gateway to any library. She really liked that, and had only recently discovered it, so Pipp and Zipp did not know, it is also why they moved their stash from the old hideout, to the library.
So with a bit of focus Sunny summoned what looked like a giant book, labeled The Book of Lore that became a portal at Sunny's command. Said portal closed after All four crusaders, plus Hedera went through. And in the castle library they came out of the book, as it disappeared again.
The crusaders then grabbed their supplies, and with a quick cheer of "CUTIE MARK CRUSADERS NIGHTMARE SLAYER, YAY!" They made their way to the main room with the fight.
Inside Cadence was playing defense while Luna was offense, sending blast after blast after Nightmare Moon, who retaliated, having drained Celestia of her magic and added it to her own, during their fight by using her anger against her. Luckily love magic was best at defense, and Cadence had been practicing after finding out about Nightmare Moon, just in case. Something that became even more important after she started dating Luna, especially when they got married six months before as Pipp and Zipp, with Scootaloo as ring bearer, and Sunny, Apple Bloom, and Sweetie Bell as flower fillies. She refused to let her wife fight the Nightmare alone.
They were so focused on each other, that they didn't even notice the crusaders entering the room, and setting up the supplies for a humiliating defeat. Something Nightmare Moon was going to regret.
Once Nightmare was in position Hedera let loose a long howl calling all three of the fighters attention to where she was standing alone.
"What is a Timberwolf doing here?" Nightmare asked herself. "I didn't call one."
Suddenly Nightmare was hit on the head by a glass bottle thrown by Scootaloo that when it broke caused an explosion that knocked her into a wall, and destroyed her fur. She then fell belly first on top of an animal trap that clamped onto her body, causing her to scream in pain only for a pie to hit her, getting on her tongue, where she found it was made by Sweetie Bell, who was a horrible cook, and she gagged in disgust at the taste before glaring at where it came from to see a small catapult firing a bag with an anti scent spell on it that also landed on her face and broke, making her wish for the pie back, when she discovered it was a bag of extra strength manure from Apple Bloom's farm, and got both in her mouth, and all over her face and body. This caused her to tear up, and gag as part of the frabic of the bag was caught between her teeth, and stuck keeping the manure that made it in her mouth in her mouth. Just in time for a bright glow to shine from the side, causing her to turn to it, in case it was something worse, since it had been steadily getting worse, only to see Sunny wings and horn out as she floated at head height, and firing a beam of concentrated light magic, she had been collecting while the others distracted her. After all if Nightmare Moon is made of dark magic then she should be week to light magic, of course she was expecting the extra strength manure to keep her occupied long enough for her spell to hit, so she wasn't expecting, Nightmare Moon to turn to face the beam, and go through her gagging mouth, and force both the fabric, the extra strength manure, and the beam of concentrated light magic down the Nightmares throat.
It still worked though, as the magic began seeping out of her before she quite literally exploded. Just a few scraps of magic, and a pile of charred, and very stinky, manure remained, that Cadence and Luna quickly dealt with after recovering from their shock.
They then decided to leave after Luna sensed Celestia on her way, having been freed when the Nightmare was destroyed. So after returning to the Golden Oaks Library, once more as Pipp and Zipp they decided to give the crusaders a lecture about not fighting ancient evil beings without training...the crusaders were still bummed about not getting their Cutie Mark's though.