Three years after RPG dungeons start appearing on Earth, researcher Keigo Yoshimara enters the lucrative world of dungeon diving! Discovering a magic skill, he storms into the dungeons, armed with his wits and a savvy business partner.

The Oracle Princess Alfina suddenly announces an ominous prophecy, yet none heed her words. But a fateful encounter with the merchant Ricardo may see the disaster averted with the power of science, mathematics and economics from the modern world!

Onigawara Shouzou, a married father of three, must put his sales skills to the test when his family and their entire house get transported to a whole new world of monsters and magic!