Three months had passed since the bell rang.
Life in Aozora looked normal again—crowded streets, school bells, evening sunsets—but Aira Hoshino knew better. The sky was quiet, yes… but it wasn't empty.
She stood by the classroom window, watching clouds drift like slow thoughts. Since losing the Echo Mark, her days had felt lighter—and heavier at the same time. The whispers were gone. The warmth in her chest had faded. Sometimes she wondered if it had all been a dream.
"Aira."
Ren's voice snapped her back. He waved a notebook in front of her face. "You spaced out again. That's the third time today."
"Sorry," she said softly, forcing a smile.
Ren studied her for a moment. "You miss it, don't you?"
She didn't ask what. She didn't need to.
"…I don't know," Aira answered honestly. "I wanted a normal life. But now that I have it, something feels unfinished."
That evening, the sky changed.
Not suddenly. Not violently. It was subtle—like a held breath. The sunset lingered longer than usual, staining the clouds with deep violet and gold. Birds fell silent. Wind stopped.
Aira felt it before she saw it.
Her wrist tingled.
She froze.
"No way…" she whispered.
A thin line of light traced itself across her skin—faint, incomplete, like a scar trying to remember its shape.
The bell tower glowed.
Aira ran.
Her footsteps echoed up the hill as memories rushed back—fear, courage, Tenkuu's endless sky. The bell tower doors were already open.
Someone was waiting.
"Sora?" Aira breathed.
The silver-haired girl turned, her expression calm but tired. Her white coat was torn at the edges, as if she had walked through storms to get here.
"You weren't supposed to return," Aira said.
Sora's eyes softened. "Neither were you supposed to be called again."
The bell hummed quietly above them.
"What's happening?" Aira asked.
Sora looked up. "Tenkuu survived, but it was not healed completely. The Celestial Heart was restored… not replaced."
Aira's chest tightened. "So the sky is still breaking."
"Yes," Sora replied. "Slowly. And this time, it isn't calling for power."
Aira swallowed. "Then what is it calling for?"
Sora met her gaze.
"A choice."
That night, Ren joined them at the tower.
"I knew something was wrong," he said, eyes fixed on the glowing sky. "I could feel it."
Sora nodded. "Your bond to Aira anchors you closer to Tenkuu than most humans."
Ren blinked. "That's… concerning."
Despite everything, Aira laughed softly.
But Sora's next words erased the humor.
"This time, Aira cannot fight alone. Tenkuu doesn't need a guardian. It needs a bridge."
"A bridge?" Ren echoed.
Sora stepped closer to Aira. "Someone who can exist between sky and earth. Someone who remembers both."
Aira shook her head slowly. "I gave up that power."
"You gave up the mark," Sora corrected. "Not the echo."
The bell rang—once.
And the sky opened again.
Tenkuu looked different now.
The floating islands were closer together, stitched by streams of light. The stars moved slower, dimmer. At the center, the Celestial Heart pulsed unevenly, like a tired heartbeat.
Aira stood at the edge of the realm, breath caught in her throat.
"It's… beautiful," Ren said quietly. "And sad."
Sora knelt before the Heart. "Tenkuu is stabilizing itself by borrowing time from your world. If this continues, both realms will weaken."
Aira stepped forward. "So what do I do?"
Sora hesitated.
"You become the echo itself," she said. "Not a warrior. Not a key. A living connection."
Ren turned sharply. "What does that mean for her?"
Silence.
Sora closed her eyes. "It means Aira will hear the sky forever. It will speak through her. And sometimes… it will pull her away."
Aira's heart pounded.
She remembered standing alone, wishing to belong. She remembered the voices that once frightened her—and the strength they gave her.
"I won't disappear, will I?" she asked.
"No," Sora said gently. "But you will never be fully ordinary again."
Ren grabbed Aira's hand. "You don't have to do this."
Aira squeezed back.
"I know," she said. "That's why I choose to."
The transformation was quiet.
No explosion. No blinding light.
The Celestial Heart responded to Aira's presence, syncing with her breath. The faint mark on her wrist completed itself—not glowing, not burning—just there.
The sky exhaled.
For the first time, Tenkuu felt… steady.
When they returned to Aozora, dawn was breaking.
Ren watched Aira carefully. "Do you feel different?"
She tilted her head, listening—to the wind, the sky, the space between moments.
"Yes," she said softly. "But not broken."
Sora smiled, relief clear on her face. "Then my duty is complete."
"Wait," Aira said. "Will we see you again?"
Sora looked toward the horizon. "When the sky remembers your name."
And then she was gone.
Weeks passed.
Life continued.
Aira returned to school. She laughed more easily now. When clouds gathered, she understood why. When storms passed, she felt the relief.
Sometimes, late at night, she stood on the hill and whispered to the sky—not asking for anything.
Just listening.
One evening, Ren joined her, hands in his pockets.
"You're smiling," he said.
"The sky's calm," Aira replied.
Ren glanced upward. "Good. Then so am I."
The bell tower stood silent behind them.
But this time, silence wasn't an ending.
It was a promise.