Disclaimer: I do not own any of the Naruto characters. I'm only playing with them for a bit and promise to put them away when I'm done.

He wanted to know why.

Why in the world a teacher as gentle as Mizuki was would suddenly break character completely and attempt not only to steal the forbidden scroll, but to kill an innocent student in the process. Rolling over to find himself alone again night after night gave him plenty of time to think about it. It made no sense to him, not then and not now.

"Do you remember that night before our Chuunin exam?" Mizuki asked him, not bothering to greet his visitor or even look at him. Ibiki had already questioned him, frustrated only that he could extract nothing. Since then, there were other things to see to, and Mizuki remained in his cell, forgotten for the most part. Iruka couldn't bring himself to even visit, still stung by the betrayal and busy caring for the students under his wing in the wake of such turbulent times.

Mizuki hardly looked worse for the wear, by neglect or questioning. Iruka heard the kinds of things an interrogator nin might do and suppressed a shudder. "Of course I do..." The image of that day burned itself into his memory, the melting sky of sunset imprinted on Mizuki's white hair. Kisses stolen and hands tentatively exploring places previously forbidden. It was the night they became lovers, tied together by their own unspoken promises.

Mizuki laughed, a dry and humorless rattle. "Obviously not." He finally turned to face Iruka. Gone was the gentle, caring expression Iruka had been accustomed to, replaced by a darkness he still struggled to comprehend. A wry smirk, a knowing glance and a barely perceptible cant of his head. "Because if you did, you would know by now that I'm not Mizuki."

Iruka blinked. At a loss for words, he could only stare and process this into something that made sense. Mizuki's half-smile widened. "He's dead. He's been dead for several months now. I killed him and usurped his place."

"No. I don't believe you," Iruka breathed. Already his heart pounded in his eardrums, thinking back to when Mizuki's demeanor first began to shift. When had it started to dawn on him that something was amiss, three months ago, four? He had been so busy, then, and felt the divide between them with only the vague thought of repairing the damage later. Always later. "I refuse to believe this!"

"Just listen. You'll get more out of me now than Ibiki ever hoped to with all his fanciful jutsu."

"Shut up!" Iruka grabbed the bars to the cell, as if they were the throat of the claimed impostor, something he could choke between his fingers.

Mizuki's expression never changed, the cruelty in his eyes remained, crinkled now by the humor he took in Iruka's pained denial. "He loved you till his last breath, you know. Swore up and down to me that you'd know the difference. I guess he was wrong. But look, I'm being rather cold and I'm digressing. They're coming, now. When they do, I'll be dead because I failed. But I thought you might want to know."

Iruka counted backwards to get control of his temper again, fingers one by one removed from the bars until he could finally step back. "Who is coming?"

"If I told you that, it would be cheating. But ask yourself, Iruka, why was I after the forbidden scroll? Who in the world might want the jutsus inside when most shinobi know a forbidden skill or two anyway? What was in there that only the Hokage would know?"

Eyes narrowed, Iruka thought about it and realized with dread certainty just what the false Mizuki was alluding to. "The seal... the seal that bound Kyuubi to Naruto."

Mizuki chuckled softly. "Very good. You always were the smart one."

But Iruka wasn't listening to him anymore, rushing out of the dingy detention center beneath the police station to the light of the surface.