Below is a walkthrough of the Special Mission / Dangerous Work main story event in Rune Factory 5.
Client: Terry
Location: Gadeus Grasslands (Recommended Level 35)
Objective: Take care of the monsters in the Grasslands
After progressing with the story, Terry will ask you to deal with some monsters in the Gadeus Grasslands. Exit the town to the northwest and follow the path west to reach the entrance to the dungeon. Save your game then head inside.
Work your way to the stone wall, defeating the enemies along the way. When you reach it, a dialog event triggers. After the event, head west to the other side of the grasslands. From there, you’ll be able to head to the depths. When you reach the Gadeus Grasslands: Depths, proceed west to trigger a dialog event leading to a boss fight. After you defeat the boss, head back to town and make your way to Terry’s Detective Agency for another dialog event, completing the event.