A/N: I'm making Rukia a vice-captain here, as it takes place after Juusanbantai Fukutaicho. Just so you won't be confused.
Captain Ukitake sat doing paperwork in his office on a cold Monday morning. It was a peaceful November day- as peaceful as it could be in the Seireitei; very normal and boring. There were, of course, the customary two voices screaming at each other in the background, but it wasn't Kiyone and Sentaro this time. Ukitake sighed and shoved himself away from his desk. When it came to Ichigo and Rukia's bickering, someone had to be the adult in the situation before either party ended up severely injured. Of course, that "somebody" was usually him.
"HOW DARE YOU INSULT CHAPPY, YOU STRAWBERRY! ICHI-BAKA!"
"SHUT UP! AND DON'T CALL ME STRAWBERRY! MIDGET! SHORTY! PINT-SIZE! NOBODY CARES ABOUT YOUR STUPID RABBITS!"
"HOW CAN YOU SAY SOMETHING LIKE THAT?! EVERYONE LOVES CHAPPY!" Dear God, were they still arguing over that? This was the longest time a fight had gone on before they had to continue it in the Fourth Division. However, Ichigo seemed to be losing the battle now- Rukia was dangling from his neck, apparently trying to choke him, and succeeding. He was turning blue.
"Kuchiki, although I hate to interrupt your training, we're needed to help with the new recruits down in the squad's barracks." Ukitake intervened quickly.
"Oh! Yes sir, Captain!" Rukia detached herself from Ichigo's throat and took her place at her captain's side. The orange haired boy mouthed a quick "thank you" to Ukitake and hightailed it out of the room as quickly as possible. The captain and vice-captain walked normally to the barracks as opposed to using shunpo, as training didn't start for another few minutes.
"You know, you're going to give him a serious injury one of these days," Ukitake said conversationally as they were walking. His tone was amused, but this was actually a valid fear. An angry Rukia was a deadly Rukia, and when she was around a certain berry boy, the risk of fatality was doubled.
"Hn. Stupid strawberry was asking for it. He deserved everything he got!"
"But you're usually the one who hits him first. You couldn't refrain from fighting him if you tried," Ukitake persisted. It was true, after all.
"Are you willing to bet on that?"
He considered it. "You know, Kuchiki, as a captain I should really be above that kind of behavior. Besides, there's no way you would win."
Now she was determined. "Come on, Captain Kyoraku makes bets all the time. And I would so win."
"If you're so sure. But this does mean you won't be able to insult, yell at, or physically attack Ichigo for an entire week. What do you want to bet?"
"Next week's paperwork?"
"Deal."
The bet was on.
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Over the next few days, Ukitake noticed Rukia becoming increasingly quiet and oddly behaved. Sometimes she would space out and glare without realizing it, or she would grit her teeth and grip the table so that her knuckles turned white. Her progress reports were sometimes nearly illegible because of how hard she had been pressing on the pen. However, she never said a word. It was as if she was afraid that if she opened her mouth, she would start screaming. He didn't relate this strange behavior to their bet- in fact, he had all but forgotten about it. It wasn't until day five that he remembered at all.
Ichigo stormed into his office, looking very frightened, confused, and angry. Emphasis on angry. Ukitake chose to overlook this. His vice-captain went rigid but didn't say a word.
"Ah, Kurosaki-san-"
"UKITAKE!" Ichigo stumbled across the room to the white haired captain's desk. "WHAT DID YOU DO TO HER?!"
"I'm sorry, what do you mean, Kurosaki-san?" Ukitake asked politely. Then he suddenly remembered Rukia's out of character behavior for the past five days. The bet! How could I have forgotten?
"THAT GIRL-" Ichigo pointed at Rukia- "IS NOT RUKIA ANYMORE!"
"Would you care to explain the problem?"
"It's been nearly a week and she hasn't even punched me in the face once! I called her a midget and she didn't even glare, and when I told her that her drawings looked like Hello Kitty gone wrong, she SMILED and thanked me for my honest artistic feedback! And look, she's sitting right there and hasn't made one smart comment about my hair since I came in! What is this madness, some kind of weird new training method?! WHAT HAVE YOU DONE TO HER?!" Ichigo was breathing heavily at the end of this. He looked at Rukia with an expression like that of a scared rabbit.
Ukitake looked slightly uncomfortable. "About that. It might have a little to do with me." He looked calmly at Rukia, whose entire body was clenched up. "Kuchiki, I think that for the sanity of you and your friend, we may need to call off our bet."
Rukia let out a huge breath as if she had been holding it in. "I think it's for the best, Captain." Then she promptly walked up to Ichigo and let out a string of insults a mile long.
"You're an idiot. Your breath smells like rotten dog food. Your hair is a mess and needs to be cut. You have no sense in fashion. Yachiru is a greater warrior then you'll ever dream of being. Kon would make a better Shinigami than you!" She kicked him in the shins with as much force as she could muster, and then walked off.
Ichigo looked immensely relieved for a few seconds before he realized what she said. "Wait- KON?! GET BACK HERE, MIDGET!"