Chapter 1: The Equation of the

The sycamore leaves curled up in the heat wave, and the chirping of cicadas, mixed with the steaming heat from the asphalt road, turned the classroom of Class 2, Grade 9 into a stuffy can. Shen Xingye pressed an icy mineral water bottle against the back of his neck. The water droplets slid down the collar of his school uniform, making him shiver. The ceiling fan creaked as it turned, lifting the strands of hair on his forehead. The tip of his pen hovered over the last big question on the physics test paper, unable to land for a long time. Those force analysis diagrams were like twisted vines, making his temples throb.

Suddenly, a sharp braking sound came from the corridor.

"Be careful!"

Shen Xingye jerked his head up, and the pen made a long ink mark on the test paper. He saw Su Wanning staggering backward while holding a stack of exercise books. The hem of her light-colored dress fluttered in the wind, like a broken-winged butterfly. The out-of-control bicycle rushed towards her crookedly, and the metal handlebars glinted coldly in the sunlight. At that moment, time seemed to slow down. He saw the fear in Su Wanning's eyes, the way her trembling fingertips released the exercise books, and the flying papers that were like pale snowflakes.

Almost instinctively, he stood up, and the desk he knocked over made a deafening crash. The test papers fluttered like snowflakes. Shen Xingye spread his arms and shielded Su Wanning in his embrace. The moment the metal handlebars scraped against his left arm, a searing pain shot through his nerves, more painful than when he cut his palm during a model airplane test flight last time. But when he looked down and saw Su Wanning's upturned face, with fine beads of sweat on her eyelashes and the ends of her hair brushing against his hot neck, the faint fragrance of jasmine mixed with her rapid breathing rushed towards him. At that moment, the pain suddenly seemed insignificant.

“Shen Xingye!”

In the midst of the noisy exclamations, Shen Xingye heard the rapid beating of his own heart. He wanted to say "It's okay," but found his throat was tight. Su Wanning's trembling fingers clutched his bloody school uniform jacket. The way she seemed to want to say something but held back suddenly reminded him of the injured sparrow he found in the corner of the playground last winter.

"Are you okay, classmate?" The boy who was riding the bicycle took off his helmet in a panic, his face as white as a sheet. "My brakes failed..."

The class monitor pushed through the crowd of onlookers and frowned at Shen Xingye's bleeding arm. "Go to the infirmary first." Shen Xingye wanted to say it was no big deal, but when Su Wanning bit her lower lip and said, "I... I'll go with you," he nodded involuntarily. When Lin Xiaoman squeezed in, he was annoyed at his own weakness. When had he, Shen Xingye, ever been so delicate? But Lin Xiaoman's words, "My goodness, is this a scene of a hero saving the beauty? Su Wanning, your face is so red!" made him somehow look forward to it, looking forward to how Su Wanning would react.

The smell of disinfectant in the infirmary made people dizzy. As the school doctor treated the wound, he muttered, "These students nowadays, why show off like this..." Shen Xingye stared at the mottled water stains on the ceiling and heard the faint sound of footsteps in the corridor. He suddenly felt a little nervous, and his fingers unconsciously clenched the bed sheet.

"May I come in?" Su Wanning stood at the door holding a stack of exercise books, and there was still dust on the hem of her skirt. She carefully placed a box of band-aids on the table, and her voice was so soft that it was as if she was afraid of scaring something away. "I'm sorry. It's all my fault for not looking where I was going..."

"It's not your fault." Shen Xingye twitched the corner of his mouth. The wound stung sharply from the iodine tincture, but he still tried to make his tone sound relaxed. Su Wanning suddenly leaned in close, and her warm breath swept across his wrist. He felt the hairs on the back of his neck stand up. "You should take good care of the wound, or it will leave an ugly scar," she said. As she spoke, her eyelashes fluttered slightly. Shen Xingye suddenly thought of the model airplane design drawings hidden in his desk. Were those crooked lines also like his heart that was beating out of rhythm at the moment?

After school in the evening, Jiang Hao put his arm around Shen Xingye's shoulder. "You were awesome today, bro! Do you want me to spread the word in the basketball team?" Shen Xingye shook off his hand, but felt a little irritated inside. He caught a glimpse of Su Wanning walking side by side with Lin Xiaoman and heard their laughter floating over. Suddenly, the shouts and cheers on the basketball court seemed harsh to him. When Jiang Hao mentioned that someone from the next class was chasing Su Wanning, he slammed the basketball against the backboard. The sound of the metal hitting the board made his eardrums ache, but the uneasiness in his heart became even clearer. What was he uneasy about? He himself couldn't quite figure it out.

The next morning, when Shen Xingye entered the classroom, he found a delicate paper bag in his desk. When his fingers touched the box, his heart started to beat uncontrollably again. The handwriting on the note was as neat as if it were printed, but the sentence "Thank you for protecting me yesterday" made him read it several times. When Lin Xiaoman's teasing voice came, he hastily stuffed the note into his school uniform pocket, afraid that others would discover this secret that held the rhythm of his heart.

During the lunch break, Shen Xingye was alone on the rooftop, adjusting his model airplane. The setting sun dyed the rusty and mottled guardrail a warm red. The wind passed over the wings, making a faint humming sound. When he heard the arguing voices of Su Wanning and Lin Xiaoman coming from the staircase, his fingers involuntarily tightened. He heard Su Wanning say, "I've already said it's not what you think," and there was an urgency in her voice that he had never heard before. Suddenly, his throat felt tight. When he hid the model airplane, his palms were covered in sweat, as if someone had discovered some shameful secret of his.

"You... Why are you here?" Su Wanning was obviously taken aback when she saw him, and her cheeks turned red. Shen Xingye looked at the notebook in her hand that was stained with watercolor, and suddenly remembered that when he was a child, he always liked to hide the collected candy wrappers in an iron box, being cautious yet full of joy. "Adjusting the model airplane," he heard his own hoarse voice say, and then, on an impulse, he added, "Do you want to take a look?"

When Su Wanning carefully took the model airplane, her eyes sparkled like stars. Shen Xingye felt something swelling in his chest. The to