The ocean has claimed almost everything. Fresh water — called hydro — is the scarcest and most important resource left, and whoever controls it controls what remains of organized survival. Food is scarce, weapons are necessary, and information about dry land — if it still exists somewhere — is worth more than any of the other three. The Smokers patrol the waters between here and wherever dry land might be, enforcing their own brutal form of order. The mission is to gather enough of all four resources to make the journey viable, evade the Smokers in the process, and find what the water has been covering.