Shiina has 2 secrets. She loves her brother Kiri a lot, and Kiri doesn't know that they are not blood related. She doesn't know what to do, she's been hiding it for a long time, and no one knows she loves him.
"This love is secret.
Secret to anybody.
However, my heart is trembling.
---Hey, I've become aware of these feelings.
Please don't notice.---"