From publisher blurb:
The From the Deep Adventure Path resumes after the PCs have returned to the city of Arbil for some much-deserved rest. But instead of finding a peaceful city, increasingly frequent and vicious raids by the tribal orcs found along the unclaimed coastlines spoil the plans of the party.
The PCs are tasked with tracking down the reason why the orcs are attacking Arbil in increasing numbers. In their journeys, the PCs will travel along the wild coastlines of Tion, encountering the untamed inhabitants that have yet to be pacified by the Protectorate, and even out across the ocean ruled by the Maquoran Fleet.
But is the true danger from across the ocean or from below it?
Also included in "Ruling Three" is detailed information on the lizardfolk race, several new psionic monsters, and information on the coastlines of the Protectorate.