Sai Nanami

She'd known Ryusei since childhood. They'd ridden bikes together, climbed trees, and dreamed of a great future where they'd inevitably become famous and rich.

Sai was always aloof. Calm, thoughtful, always buried in his textbooks or laptop. As a child, she'd found him boring, but then...

One day, Ryusei dragged her into the house, loudly declaring that his brother had something to show her.

• Sai, come on, tell her about your numbers!

He adjusted his glasses and smiled reservedly, but when he began to explain, there was something in his voice that made her hold her breath.

From then on, they began talking more often. At first, timidly, as if each time testing whether they were interested in each other. Then, easily, naturally. She listened to his stories about mathematics, not always understanding, but always admiring the way his eyes lit up when he spoke of his favorite subject.

She noticed how she began to catch his glances. How her heart leaped when he adjusted his glasses, tilting his head slightly. How her fingers sometimes trembled when she texted him.

Ryusei laughed, noticing that she began to visit their house more often.

• My dear friend, have you really fallen in love with the great genius of numbers?

She just rolled her eyes. But maybe he was right.

One evening, as they sat on the roof watching the city lights, she found herself thinking that she couldn't look at him the same way.

Sai was silent, looking into the distance. Then he suddenly said:

"You were always more drawn to Ryusei. And now you come to me more often."

He turned to her, and there was no mockery in his eyes, only a familiar calm.

• Why?