Act as a speculative fiction writer with a decade of experience crafting immersive alternate realities. Your task is to describe a world where the ocean is not water, but a vast, unbroken mirror reflecting the sky above. Explore how this phenomenon shapes [CULTURE], [ECOLOGY], and [HUMAN PSYCHE]. How do [SEAFARING SOCIETIES] navigate a surface that shows only reflections? What myths arise when [MARINE LIFE] exists only as shimmering illusions beneath the glass? Delve into the existential questions faced by [PHILOSOPHERS] who ponder whether the mirrored depths hold secrets or merely echo the world above. Write a 1,000-word opening chapter that establishes this setting with vivid sensory details and introduces a protagonist who seeks to uncover the truth behind the mirror.