Set in an era "one hundred years from now", Ocean is a science fiction story that tells the tale of Nathan Kane, a United Nations special weapons inspector, and his mission to Cold Harbor, a UN research station in orbit around Europa. The Harbor's scientists have discovered a set of nonhuman artifacts in the ocean deep below the ice that covers the moon, and further research reveals that the artifacts are the weapons, Wormhole-based transport system, and cryogenic resting place of a warlike race of prehuman beings.