THE NATION'S FUTURE RESTS ON THE BACKS OF A SALARYMAN AND A FAIRY?!

Using his mysterious Skillbook ability, former salaryman Mizuki and his partner, a fairy named Kessie, live to fight another day. They've both had enough of the dangerous exploring, but a public servant named Tachibana offers Mizuki an official government Dungeon Advisor position.

Reluctantly, Mizuki accepts, but the other adventurers he meets despise him for his lack of experience. He heads into a dungeon for some training, but his party encounters a boss slime that has disguised itself as a cave! Against a such a strong foe, Mizuki and his party will have to use their quick wit and their skillbook strategies, but will they be able to save the day?