There was an incident. It was wrong. Here’s my eyewitness account.

I was in my bathroom, getting ready for the day. Button and Siah were in his room. They had been given clear instructions: he was to clean his room, she was to help him, and she was NOT to do it for him (he has a tendency of reneging on his responsibilities and sticking them on her). It had been awhile – the room should’ve been close to done.
Next thing I know, I hear Siah hollering at the top of his lungs. And about 20 seconds later, Button rounds the corner to the bathroom and very matter-of-factly reports that Siah is NOT cleaning up his room. As she’s going on in some detail about all that he’s NOT doing, Siah rounds the corner, too.
His face is red. His eyes are puffy. His face is soaked in tears. And so is his chest and his shirt. And he’s boiling mad! He starts waving his finger in the air, shouting at the top of his lungs, and ripping into Button. Even I was intimidated!
I couldn’t make much out, but it was clear that he thought a terrible injustice had been committed in Button coming to tattle-tale on him. I asked him to take a deep breath and to tell me in a calm voice what had happened.
It seems that Button and Siah were cleaning up the room as planned. But then they both got distracted and started playing. She pulled out the trains and made a terrible mess in his room. Then, when she was done, she told him he needed to clean it up. He retorted that no, she needed to clean it up because she made the mess. And then she quipped back, “I’m going to tell mom you’re not cleaning up your room!” And off she went. And off HE went!
How did the messy room caper end? Button was sent to her room for a time out. Siah’s anger subsided quickly (he thought he was going to get in such terrible trouble, and he knew he wasn’t able to articulate as well as his sister – what hope did he have?). I spoke gently to Siah about how he didn’t need to let his anger control him – he could trust that if he remained calm, he would get justice. And then I went and talked to Button about how awful it is to try to get her brother in trouble like that – it’s like lying, and it’s like what Cain did to Abel. She got it (I think).