The protagonist, Tsumugu, had an older stepsister, Tsumugu Nozomi, who loved him dearly.

Tsumugu thought that Nozomi couldn’t let go of the idea of him as a younger brother, but little did he know that Nozomi had a stronger brother complex than he imagined. Nozomi dreamed of a future where they could be happy together.

However, when faced with the barrier of being siblings, Nozomi felt she had to give up on her dream. Just as she was coming to terms with this, Tsumugu discovered that they were actually step-siblings.

In an attempt to avoid confusing Nozomi, Tsumugu tried to keep this revelation a secret, but it quickly became apparent. Nozomi, no longer willing to suppress her feelings, decided to release them all at once.