Ichigo stared straight ahead, his mouth open. This had to be a joke, had to be someone's idea of a warped practical joke. There was no way that he was seeing this!

His protests did not remove the sight of Byakuya dressed in normal clothes and taking role from where he stood in the front of the room.

Looking out of the corner of his eye, he tried to see Renji's face. The redheaded shinigami looked completely in shock at what was happening. Even Rukia looked as if someone had hit her in the head with a board at seeing her adored older brother there with them.

"Abarai!" Byakuya snapped at his vice-captain. "What are you doing dressed like that and not in proper uniform? Report to the office now!"

Renji gave a startled but brisk "Hai," and made his way to the office, not before Ichigo had heard him swallow the "t-" he's made, catching himself before he gave away his captain's title.

"Now, as for the rest of you, there are going to be a few ground rules for today's class. I am your teacher for today. You will therefore address me as Kuchiki-sensei. There will be no talking among yourselves, and no horseplay. I expect you to be attentive and to do your work. Is that understood?"

Tatsuki raised an eyebrow suspiciously and raised her hand, interrupting whatever else Byakuya meant to tell the class.

"Kuchiki-sensei, doesn't that mean you are related to Rukia?"

Byakuya looked at her as if he considered the question impertinent- which it really wasn't. In fact, for Tatsuki, it had been damned polite, expressing not even a hint of annoyance but merely polite, almost deferential interest.

In a way, that worried Ichigo, and he meant to speak with Tatsuki about that later. The fact she was being so respectful to Byakuya had him wondering if she had picked up on anything that he needed to worry about as well.

Still, he did not bother to hide his own smirk at Byakuya's discomfort.

"I am not aware of having any blood relatives of that name, no. Now, if you will remove a sheet of paper from your notebooks, it says that you are to have a math test today."

Ichigo kept his eyes carefully on his paper as he completed the quiz, smiling as they checked the answers, his mind more on Byakuya's comment than the material.

Of course not, you dumbass! She's your wife's little sister. If you two were blood related-!

Ichigo tried not to grimace at the thought. I mean, while Rukia was perfectly capable of looking and even acting as obnoxious and stuck-up as he felt Byakuya was at times, the thought of it being anything else made him feel slightly nauseous.

Still, it was swallowed quickly enough by the eyebrow arched in surprise as he noticed Ichigo's quiz and Ichigo smirk widened as he watched Byakuya –Kuchiki-sensei, my ass! –take in the perfect score.