The lands of the Ninth World are vast and filled with the leftover marvels of prior worlds. But the ancients didn't live and work their strange ways only upon the land, and the secrets, treasures, and deadly dangers of the past also lie beyond the vast horizons - and beneath the foam-flecked waves - of the Ninth World's great ocean. Ancient ruins? Secrets? Treasures? Gods? Any of these, and rewards yet unimagined, may await discovery for those willing to leave the comforting familiarity of dry land and accept the ocean's cold, dangerous embrace. Into the Deep introduces new creatures, cyphers, and artifacts usable in any Numenera campaign.