Their search began at the Whispering Market, where vendors sold bottled echoes. An old woman with sea-glass eyes pointed toward the Spire, the city's broken clock tower. "She asked about the Drowning Hour," the woman rasped. "The moment when the tide is so high the city's foundations sing."

"Follow the echo," Ricky said.

"Luna!" Abby cried.

They found her in the deepest chamber, the Resonance Well. She was sitting cross-legged on a natural pillar of basalt, eyes closed, smiling. Around her, the echoes of dripping water, distant thunder, and her own name—called by Abby and Ricky days earlier—wove together into a strange, haunting lullaby.

"The song isn't outside. It's inside the silence between echoes."

Abby held the tattered sketch she’d made of her younger sister—charcoal smudged where Luna’s smile used to be. "She wouldn't just leave," Abby whispered, her voice swallowed by the damp, salty wind of the City of Echoes.

They climbed out of the City of Echoes as the sun rose over the caldera rim. Luna didn't speak much on the way back. She didn't need to. The search was over.