The blueprint lay on the polished sandbearer wood table, not as a piece of paper, but as a catalyst. For Ren, it was the solution to a problem. For Ganyu, it was a source of bewildered pride in her little brother. But for Xianyun, it was a flame reignited.
Her golden eyes, usually calm and analytical, now held a fervent, brilliant light. She saw beyond the lines and annotations; she saw the whirring of gears, the controlled flow of elemental energy, the hum of a perfectly calibrated machine. She saw a future where a shivering child in a remote mountain village could be warmed by a gentle, controlled heat. It was an invention born of simple, compassionate observation.
It reminded her so keenly of Guizhong that it made her ancient heart ache with a bittersweet pang. Guizhong had believed that wisdom should be a tool to protect and comfort mortals, not to rule them. She had filled her notebooks with designs for clever devices meant to make life easier for the people of their burgeoning nation. This blueprint… it felt like a lost page from one of her friend's journals, miraculously brought to life.
"The theoretical principles are sound," Xianyun declared, her voice resonating with an excitement she rarely showed. She tapped a slender finger on the diagram of the regulator. "This concept of modulating energy flow through variable resistance… it is efficient. The components can be crafted by mortal hands, but the precise calibration of the coil will require adeptal refinement for at least testing purpose and understanding the principles. My workshop has the necessary tools."
She looked up, her decision made, swift and absolute. "We must return to Mt. Aocang. Immediately. We cannot allow this spark of an idea to languish. It must be forged while the inspiration is hot."
The words, so full of purpose and creative fire, landed in the quiet room with the weight of a judge's gavel. Ganyu, who had been looking at the blueprint with a dazed smile, felt a sudden, sharp jolt, as if she'd been doused in cold water.
Return? Immediately?
Her smile faltered, her amethyst eyes clouding over. The past week had been the happiest, most fulfilling period of her long life. She had a home to come to, not just a place to sleep. She had a family who waited for her. The thought of returning to a quiet, empty house, of eating her meals alone, of her day being defined only by the endless stacks of paperwork… it was a bleak, lonely prospect that made her chest feel tight.
"Oh," she said, her voice small and hollow. "So soon?"
Ren immediately noticed the shift in her. The bright, protective energy that always surrounded her seemed to dim, replaced by a quiet, heartbreaking sadness. He saw the way her shoulders slumped ever so slightly, the way her hands twisted in her lap. He felt a pang of guilt. His invention was the reason they had to leave.
"We'll come back, big sister," he said quickly, leaving his seat to stand by her side, his small hand resting on her arm. "Master just needs her special tools on the mountain to build the heater. Once it's done, we can bring it back here to test it! We'll be back before you know it."
Ganyu looked down at him, her eyes shimmering with unshed tears. She forced a wobbly smile. "I know, Ren. Of course. It's a wonderful invention. It will help so many people. It's… it's important work." She was trying to be supportive, to be the diligent and understanding person she always was, but her heart wasn't in it.
The final evening was a quiet, somber affair. The usual cheerful chatter was gone, replaced by a comfortable but heavy silence. After their meal, Ganyu didn't suggest a game or a story. Instead, she simply patted the silk cushion beside her on the long couch on the veranda.
"Come, sit with me for a while," she whispered.
Ren snuggled up beside her. Without a word, she gently lifted him into her lap, her arms wrapping around him in a hold that was both possessive and infinitely tender. It wasn't the breath-constricting, overjoyed hug from before; this was a slow, desperate cuddle, an attempt to memorize the feeling of him, the weight of his small body against hers, the soft texture of his messy hair as she rested her chin on top of his head.
They sat like that for a long time, watching the lanterns in the garden sway in the gentle night breeze. Ganyu didn't speak. She just held him, her embrace a silent testament to how much he had come to mean to her. Ren, understanding her need for this closeness, didn't squirm or complain. He leaned back against her, feeling the rhythmic, steady beat of her heart, and felt a profound sense of being loved. He was going to miss this, too.
The morning of their departure was overcast, the sky a blanket of soft gray that mirrored Ganyu's mood. She insisted on walking them to the grand gates of the city, the same gates they had entered with such wonder only a week before.
The goodbyes were brief and choked with unspoken emotion.
"I'll have the house kept ready for you," Ganyu said, her voice thick. "I'll… I'll air out the rooms every day."
"We will appreciate that," Xianyun replied gently, placing a comforting hand on Ganyu's shoulder. "You have given him a wonderful gift, Ganyu. A home. We will not be strangers to it."
Ganyu then knelt down in front of Ren, her amethyst eyes pleading. "You'll promise to come back soon?"
"I promise, big sister," Ren said, and he meant it with all his heart. He reached out and gave her a tight hug around her neck, a gesture she returned with a desperate, clinging force.
When she finally let him go, her cheeks were wet. She stood up, wiping her eyes with the back of her sleeve, and tried to smile. "Be safe, both of you."
Xianyun nodded, then scooped Ren into her arms in the familiar princess carry. With a final, lingering look at Ganyu, she turned and, with a powerful gust of Anemo, they lifted into the air, soaring up and over the city walls.
Ren looked back, his heart aching. He saw Ganyu standing there, a small, solitary figure in blue, watching them go. He saw the house on Feiyun Slope, their house, nestled amongst the golden roofs. He kept watching until she was just a tiny speck, and then nothing at all.
As the Harbor receded behind them and the familiar, jagged peaks of Jueyun Karst rose to meet them, Ren felt the shift in the air. The sadness of their departure began to fade, replaced by the thrum of excitement emanating from his Master. He looked up at her face. Her expression was focused, her golden eyes fixed on the horizon, on her mountain, on her workshop.
She looked down and met his gaze, a rare, brilliant smile on her face. "Are you ready, Ren?" she asked, her voice carrying over the rushing wind. "The real work begins now."
Ren nodded, a new sense of purpose washing over him. He was leaving one home, but he was returning to another. And he was about to help an adeptus build a revolution.