"What's with that attitude? Is that how you talk to your sister?" "You're the one who started it."

Saeko, the older sister, and Kaoru, the younger brother, always bickered like this whenever they saw each other. Saeko would start an argument, and Kaoru would retort. That was all they ever did.

One day, Kaoru, who was filled with resentment, blurted out something he shouldn't have said.

"I don't want to see your face or hear your voice. I don't think of you as my sister anymore."

At those words, Saeko's face crumpled, and she ran to her room. A few days later, Saeko took an unexpected action...