Defeat Dirty Archaeologists at the boundaries of Algon. Afterwards, speak to Captain Diana at the Algon Post. Use your quest tracker to see your progress.
Captain Diana: You have been doing a good job of keeping the Dirty Captain Diana: Dozen in check so far. It seems that since two of the Captain Diana: Great Three have fallen, their efforts are Captain Diana: concentrated on finding and unleashing the wrath of Captain Diana: the last. NakanoAzusa: I agree. Captain Diana: They haven't led us to anything so far, so it is of no Captain Diana: benefit to us to let their research go on. Dirty Captain Diana: archaeologists are coming up from the outskirts of Captain Diana: Algon. Find them and destroy them. HiiragiKagami: How am I supposed to stay clean when all we're doing HiiragiKagami: is fighting these dirty men?
Reminder Dialog
Captain Diana: Please continue to take this Dirty Dozen threat Captain Diana: seriously. I can't afford to lose you, neither to apathy Captain Diana: nor to carelessness in battle.