The timeline begins five years after hordes of monsters which are called orcs in past documents had appeared and had begun to constantly terrorize the people.
They are plundering, killing and kidnapping young women for their reproduction as there are solely male orcs.

The kingdom tried to root them out by mobilizing the army but failed because of the hit-and-run tactics of the monsters.
At last they formed a new counter-plan.
Small monster hunting bands were created from veterans and adventureres called MUT and imposed with the right to demand any cooperation from the people they are defending, including free housing and the right on any woman.

At the beginning of the story three people of MUT are coming to a certain rural town at the frontier of the kingdom to root out nearby monsters.