I nearly broke my neck as I turned my head around with all the speed I could muster to look behind me. There she was, Nagato, behind me where I had left her. I turned my head around again, only to see Nagato staring back at me, standing in front of me, blocking my way out of the room.

I don't think I can take much more of this…

"Wah… What are you…?" I stammered at the Nagato in front of me.

She raised her head slightly to look me in the eyes, and cocked her head a bit.

It can't be! It's –

"According to local time, I appear to have lost 27 hours, 42 minutes and 13 seconds of my memories between this moment and when you and I were in the same location on the school's field the previous day. This is an inconsistency I would like to resolve with your aid."

"N-Nagato?" Asahina-san stuttered, her eyes as wide as saucers, her head kept turning back and forth between the Nagato in the doorway and the one in the room with her. "W-what's going on?"

"Another one?" Koizumi asked curiously, wearing a smile that was slightly ruined by a twitch at the corners of his mouth. "I see…"

Bullshit, no you don't! You're just as lost and confused as the rest of us are!

The Nagato in front of me continued staring at me, and somehow, I could just tell that she was the real deal.

"What happened? How did you get back? I thought you were away sick – well, kinda."

Nagato blinked. She then turned her head and noticed B. Nagato walked soundlessly past me and stopped right in front of B. Both of the Nagatos just stared at each other with their subzero stares.

Then Nagato turned to face me, expression still unchanged although she'd just met a perfect replica of herself… or was she the replica? Hadn't there merely been a mindswap?

"I do not understand," Nagato stated plainly.

Huh? Oh, you gotta be kidding me!

"You were unaware of the personality transfer?" Koizumi asked, raising an eyebrow.

"…Yes." Nagato gave Koizumi a critical look. "Please, tell me more."

"Well, you see –" I started off but was cut off by Nagato B.

"This unit's personality encountered a systematic error, becoming unable to fully operate under normal conditions. The failsafe programs were initiated to protect the unit and its social interactions. The previous thought patterns and memories the unit had acquired were transferred for proper analysis and program repair. Diagnostics are still in progress…" Nagato B gave Nagato what could be seen as a deadly glare among the Nagatos (nothing most people would even notice). "You should not be here. You are endangering the mission. I am your replacement until orders to the contrary are received. You will vacate this realm of physicality immediately and seek assistance according to the proper protocols in the data stream networks or be terminated."

… What?! Just hold up a moment here!

"I am here as per my orders, sanctioned by the Integrated Data Sentient Entity. I have not received orders pertaining to my release. I am operating within the parameters set forth in my original orders. No error other than a loss of personal time has occurred. There is no need for a backup personality. I am fully capable of carrying out my mission. It is you who are endangering the mission," Nagato said, with a stare that could have easily gone past -273.15 C degrees in its coldness (nothing all that different from normal again, but for me, that furrowing of the eyebrows that could only be measured in nanometres was very impressive).

The two Nagatos stood face to face, little noses almost touching. The sudden tension in the room was so electrifying I think we could have solved the world's energy crisis simply by cracking open the window. Asahina-san's eyes were practically popping out of her skull while she trembled in the scary atmosphere. Even the usually collected Koizumi was gritting his teeth, his perfectly white teeth gnashing together roughly.

"Localized data-lockup initiated," the two Nagatos said swiftly in perfect synch.

The faint glow from the window suddenly disappeared. Then complete darkness covered us. A darkness darker than even night, it went past a lack of light until it became its own force, heavy on my shoulders like gravity.

Then slowly, I could see again. I was inside a rectangle, the walls glowing a faint blue with which I could make out shapes. A perfect grid of squares roughly 10 centimetres covered all surfaces, the lines appearing to be the source of light as they faintly glowed against the dark walls surrounding me.

I think we were still in the same room, it certainly had the same dimensions, but all the furniture had disappeared.

I then felt something squeezing my arm tightly. I turned my head and noticed that it was Asahina-san holding onto my arm with both of her hands in the faint light. She held her face against my shoulder with her eyes tightly shut. Woah… Every time she gets close to me like this I think I can feel my heart skip a few beats.

"Aah!! Wah-what's g-going on?!" she squeaked like a mouse.

"My word, what's that over there?" I heard Koizumi's voice on my other side. How'd he gotten over there?

I turned to see what was so mysterious and saw Koizumi pointing at a bright spot in the middle of the gridded rectangle. I hadn't noticed the almost pure white light because it didn't seem to give off any glow. It was just a bright spot but around it, the familiar darkness remained the same, encasing the light.

I could hear unrealistically fast muttering now and it seemed to be coming from the bright spot. It was Nagato's space code magic. This was almost like that time Asakura had tried to kill me and Nagato had saved me.

The light started to fade, becoming dimmer, as it revealed the two Nagatos still standing face to face. It was an odd sight; the light seemed to be coming from their bodies and their hair and clothing billowed as if a strong wind was blowing them. And throughout all of this, the fast paced muttering that sounded almost like a rewinding tape continued, from both of them, in seemingly perfect harmony.

This was bad, I could just tell. They were fighting weren't they? I worriedly looked at Asahina-san, worried if a similar bloody fight as the other one I'd experienced between data interfaces waited for us. Last time, Nagato had been severely injured as she was forced to protect just me, and now there were three of us. Would Nagato B resort to such cheap tricks? If she really was like Nagato when I'd first met her, I found it highly unlikely, but I still felt fearful.

Both of the Nagatos fair skin softened to a glow through which we could see their features, not that anything besides the flowing clothes and hair had changed, only their lips quivered with superhuman speed.

"What is this?" Koizumi asked, transfixed by the two glowing girls, just like I was.

"I think… I think they're fighting…"

"Fighting?"

"Yeah, using that space magic of theirs, altering data. I think they're trying to lock each other out so they can delete the other or something."

"…Amazing…"

The air around the two identical girls seemed to warp and twist around on itself. The temperature began to rise and Asahina-san held on to my arm even tighter, cutting off my circulation to my fingers.

Suddenly the Nagatos both took a step back into a low, wide stance, pulling back an arm, ready for what looked like a punch. Like mirror images the girls stood, still muttering indistinguishably, until they both threw a punch, their fists colliding.

Even though I was expecting a loud bang, all sound seemed to disappear with the collision. I couldn't even hear my own excited breathing or the pounding of my racing heart anymore. But there was a brilliant flash of light. It filled the room, burning my eyes. I'm not sure if I was able to close my eyes, since the white intensity seemed to be there no matter what I tried.

When the white brilliance finally disappeared, we were back in the room, complete with the window on the far side and surplus desks against the walls, with even the spider webs back in their corners.

The Nagatos stood still in the centre of it all… no, they weren't standing anymore, they didn't have the legs to do so. Two bodies floated in the air with no legs, slowly growing smaller as what appeared to be small particles falling from their bodies. As the pair disintegrated, the inexistent wind blew away the particles until they disappeared from sight.

"Nagato?" I asked hesitantly.

The one I knew to be the real Nagato turned her head to look back at me over her shoulder. She gave me a melancholic look that ripped my guts apart inside.

"I'm sorry… we couldn't… go to the… library again, today…"

"No! Don't say that!" I shouted desperately as Nagato's hands began to break apart along with her hips. The process was getting faster.

I tried to move, but my legs were frozen in place. No matter how much I tried to will it, they wouldn't budge. I was frozen solid by fear.

Asahina-san started sobbing against my sleeve. Apparently she'd mustered the courage to look at the world again, only to find one of her friends disintegrating.

From the corner of my eye, I could see Koizumi trembling. I guess he was suffering the same fate as me. He stood wide-eyed, mouth agape at the disappearing Nagato.

"Good… bye…" Nagato whispered as the dematerialization suddenly jumped past her shoulders and up her neck.

The two floating heads of Nagato and her copy disappeared so instantaneously into sand like fragments that it seemed like they dissipated as wholes.

The final particles left behind by the two identical girls swirled around the place where they had stood, until they too vanished from my sight, leaving nothing but the empty room with us behind.

"Yuki!" I screamed, finally managing to raise a quivering hand towards the spot where the taciturn girl had stood.