Speak to Apothecary Malthus at the Apothecary Camp.
Even the earth cannot hold back the tide of death washing over it. Corpses walk the land, spreading their putrefaction with alarming speed.
A small expedition has made its way up the western cliffs and rests near Whisper Gulch. Take a look for yourself, [player]. See if you can learn their purpose and dissuade them from bringing their poisons into our lands. Travel southwest from the post, toward the cliffs overlooking the western beach. Their camp will be west of the excavation at Steel Gate.