Knox was walking through the corridors of the School of Friendship late at night. This would've been strange, if not for the scroll he'd received earlier that day while Cozy was out "running an errand." The scroll had been sent by the new headmare, asking if Knox was ready to return to his duties as janitor. After his mandatory time off had ended, he hadn't felt comfortable leaving Cozy alone at night, so he'd requested a few more weeks off to adjust. Now, though, he felt like he was ready to return to work. He now felt more comfortable leaving Cozy home alone. He knew he could trust her. After all, she hadn't done anything nefarious for quite some time now. It wasn't like she was hiding something.
Something about that last thought tugged on the back of Knox's mind as it passed, but he paid it no mind.
Anyways, he'd gone to the school and discussed his return to work with Sunlight (or whatever her name was), and now here he was.
To everypony else, it looked like he was just casually strolling through the halls. To him, this was the first part of his job. He walked around the school to make sure nocreature would get locked in. After he finished this step, he'd move on to his favorite part of the job.
As he came to a stop near the front doors, having completed his surveillance of the building, he smiled broadly. He'd missed this part. He lit his horn, and his magic enveloped every lock on every door, window, and skylight in the building. Then, he activated them all, sealing him in for the night. At this point, he'd been doing this long enough that he didn't even need to think about where the locks were or what kind they are. He simply used his magic the exact same way he had every night for over two years.
Something seemed different about it tonight. On a typical night, he'd felt pleasure in securing himself within the school's walls. It had made him feel safe and secure. This was not what he felt now. Now, all he felt was a strange sensation of having cut himself off from something. Something he couldn't be closed off from. Something else he needed to secure. Something else he needed to keep safe. Somepony else he needed to keep safe.
'Cozy can handle herself,' he tried to reason with himself, 'she almost took over Equestria, remember?'
'Yeah, but she wasn't traumatized back then,' his mind countered. 'What if she has a panic attack? She could be falling into a heap on the floor right now, and you just completely sealed every entrance she could use to get to you.'
'Cozy is creative,' he thought with finality. 'She'd find a way in if she had to. And she has others who care about her, too.'
With that, the debate with himself came to a close, and Knox moved on to the typical sweeping of floors, dusting of shelves, and cleaning of puddles of disgusting unknown substances.
He turned the corner into the hallway where he'd first met Pinkie... and his heart skipped a beat as he very nearly ran into an all-powerful draconequus.
"What the?" he asked to the air where the draconequus stood just seconds before. "Discord?"
"Knox, my friend!" exclaimed the lord of chaos from behind him. "I heard you'd be working tonight."
He turned around and found Discord standing less than two feet behind him.
"I didn't even know until this afternoon," said Knox. "How in Equestria did you hear about it?"
"Why through the grape vine, of course!" exclaimed Discord as he pulled a grape vine from a crack that spontaneously formed in the ceiling and held it up to his ear.
Knox facehoofed.
"Why are you here, Discord?"
"Well, I had a question only you could answer. Since you had to work tonight, that means Cozy is all alone, right?"
"Why do you ask?" questioned Knox, suspicion rising in his voice.
"Why, it's just because I know how much she's been depending on you. I wouldn't want her to think you didn't care about her well-being."
"She knows perfectly well how much I care. I'd stake my life to protect her if I needed to, but that doesn't mean I always have to be there."
"Who are you trying to convince?" Discord asked. "Me... or yourself?"
"You, obviously." he replied. "Cozy can handle herself. I have no need to worry."
In all honesty, he wasn't sure if that was true. Perhaps he really was trying to convince himself.
"But what about her panic attacks?" Discord countered as he pulled a calendar out of nowhere and began glancing over it. "Haven't those been getting more frequent lately?"
Knox visibly gulped. "I... have doubts, I'll admit. But that doesn't mean leaving her alone was the wrong choice!"
"And those nightmares she used to have? What if those decide to make a comeback?"
"Please," he dismissed with a wave of his hoof, "those never stopped to begin with. She simply learned to deal with them. Besides... Wait a second! How did you know about those?"
"Oh please," said the demi-god as he gestured a claw down the hall where a grape vine was still slowly growing from the ceiling.
"You know you're cleaning that up before you leave, right?" Knox asked jokingly, sneakily trying to change the subject.
His attempt worked, and he continued his work for most of the night uninterrupted. Discord, for some reason or another, had decided to follow him around and maintain somewhat pleasant conversation. Occasionally, he'd stop following Knox and simply stare at the floor for a moment. Then, he'd smile wickedly and teleport back to Knox's side.
Overall, even with Discord around, it had been a fairly uneventful night. Knox's thoughts kept drifting back to Cozy and the possibility of her needing his help, but he tried his best to ignore it.
Then, he heard it. As soon as the sound reached his ears, he went into a full sprint towards the room he knew the sound was coming from, leaving a very surprised Discord in his dust.
He quickly weaved his way through the corridors until he was standing directly in front of the library doors. Emanating from inside, he could hear what was undoubtedly the very familiar sound of little pegasus wings flapping in the large room. He swung open the doors with his magic... and found it empty.
"Hello?" he called into the room. He couldn't have imagined that, right?
His suspicions were confirmed when out from behind one of the bookshelves near the back of the library came none other than Cozy Glow.
"Cozy? What happened?" he asked frantically as he ran over and hugged her. She winced as his hooves wrapped around her, and he soon saw why.
Cozy had scrapes and cuts all over her body. Her hair was tousled, and she had a large bruise on her foreleg.
Rage filled his mind as he cradled her injured form in the library. Not rage at Cozy, for having somehow broken into the school. Not rage at Discord, for having disappeared right when Cozy needed assistance. Not even at whatever or whoever had done this to Cozy. It was at himself. After all, none of whatever happened to her would've happened had he been with her. He'd failed to keep her safe. He'd failed to protect her.
"Knox?" asked a weak voice from his arms.
"Yes, Cozy?"
"You can let go of me now. I'm fine, really. Nothing broken or bleeding."