"Ha!" you declare with a triumphant note, pointing at the girl with a slightly-shaky finger. "I knew it! Ninja!"

You almost miss it, thanks to the ache in your skull, but she definitely flinched at that accusation. It gives the lie to her following remark, "I have no idea what you're talking about."

"I might even believe that, if you hadn't just been lying in wait for me."

"I wasn't lying in wait! I was just going to the infirmary!"

"And yet I didn't see you at all, in this hallway that has absolutely no place for anything larger than a mouse to hide."

She sniffs disdainfully. "As if it's somehow my fault that you're completely ignorant of your surroundings."

"Excuse me? I knew perfectly well that somebody was watching me, Miss Invisible Girl."

"I was not invisible!"

"And yet you appeared out of nowhere after I sent out a-" You stop, catching yourself at the last moment - or perhaps a bit later than that, to judge by her keen-eyed expression. "Wait. Forget I said that."

"No," she retorts. "And you still haven't answered my question. What did you do?"