The Edge of Europa
They didn’t believe the first patrols who reported the phenomenon. Too long in the wilderness must have addled their brains, scoffed the civil servants in the warmth of their coral-caves as they cast away the shell-engraved reports. The patrol commander despaired and told her troops to be careful when they took the high patrols, swimming near the ice-roof of the world.
It was a shoal-herd who went first. His herd of fattened fish had drifted higher than usual, following a thick flow of krill. While they feasted, he had idly poked at the ice-sheet with a flipper, expecting its eternal solidity.
Instead it cracked, revealing uneven caverns melted through its mass. The shoal-herd only hesitated a moment, for what were a few lost fish compared to an explorer’s reknown.
There were many tunnels, but he favoured those which led upwards, determined to find the edge of the world. At last the water, the world itself, stopped. He pointed his beak beyond and tasted the choking emptiness unimagined by his people.