The Sea Between The Walls

Within the walls of a colonial vessel, ocean water was once used as radiation shielding. Over time, the life hidden inside that water changed. Sea slugs developed sentience, formed a community, and came to know the enclosed waters between the ship's walls as the whole of existence.
But beyond the sea they know are dry passages, silent corridors, and the remains of the humans who built the world around them.

As the sea slugs begin to explore the interior of the ship, they search for answers about where they are, what happened to the beings who came before them, and whether their world is truly all there is. Their discoveries lead them deeper into the vessel, to stored memories, forgotten truths, and eventually the bridge, where they see a planet waiting below.

From the memories they uncover, they come to understand that the planet is Earth. Beyond the walls, beyond the ship, are vast open oceans unlike anything they have ever known.
With hope, uncertainty, and the remnants of humanity's failed return before them, the sea slugs make a plan to descend to the planet below and begin again in the waters of Earth.