I was sprinting down the hallway with one sock on, hopping like a confused flamingo, when my little sister stuck out a plastic sword and nearly chopped my ankle off.

"Mina!" I yelped, windmilling my arms. "Do you want me to crash into the fish tank?"

She stood in her polka-dot pajamas, grinning like a tiny pirate queen. "You stole my blue marker yesterday. This is justice."

"I borrowed it."

"You left the cap off."

That part was true, but I wasn't admitting it before school.

My name is Zachary. If arguing were a competitive sport, Mina and I would have enough gold medals to sink a ship. We fought over the bathroom sink, the last pancake, and whether my dinosaur drawing looked 'fierce' or 'like a potato with teeth.'

Mina was impossible. She hummed while I read, touched my stuff, and asked weird questions like, "If turtles wore shoes, would they need four or just two?" That's a difficult question when you're trying to build a volcano for science class.

That afternoon, while rain drummed the windows, Mina knocked over my cardboard volcano.

I had spent two days painting it. The mountain split with a sad crunch.

She froze. I froze. Pickles the cat leaped off the table like it was erupting for real.

"I didn't mean to!" Mina said.

I was hot with anger. "You ruin everything! I wish you would just stop being in my way for one single day!"

The words flew out before I could catch them.

At that exact moment, thunder boomed. It sounded close, like a giant knocking on our roof.

Mina's eyes went round. She pointed at the dining room wall. "Zachary," she whispered. "The wallpaper."

Our old dining room wallpaper had tiny silver stars. Usually, it was boring. Now, one star was glowing.