Life on the other frontier, below the waves of Earth's Oceans, the Martian seas, and the miles of ice that hide the Oceanus Noctis on Jupiter's moon, Europa. Histories and geography of the various seas are included, as well as information on different naval, commercial and eco-terrorist organisations that have oceanic interests.

Includes templates for aquatic parahumans, bioroids and cybershells; marine technology and vehicles; and the Aquatic Vehicle Modular Design System.