Petruvio is an older adventurer who got a good-paying job as a teacher for a young noble who plays adventurer. This young man has more money than brains and instead of using qualified men to round out the team, he hired three good-looking maidens.

Now, someone told them about Shroom Dungeon. Worse, they insist they want to visit (despite not knowing what it is). There is no choice and the old adventurer has to return. Despite having vowed never to do so. For he has a history there. In fact, a legacy.

This is a stand-alone story taking place in Shroom Dungeon.