Investment banker Mizuki was relegated to a company branch in the countryside, only to arrive and find it transformed into a dungeon--one connected to another world! While searching for survivors, he met the talkative fairy Kessie and obtained the mysterious Skillbook ability. Businessman Horinomiya hears about Mizuki's skillbook, and as part of his schemes as CEO, he convinces Mizuki to clear a dungeon for him. Horinomiya also sends a female adventurer named Carol, and she is so incredibly powerful that success seems all but guaranteed...until a monster worthy of being the last boss appears and causes chaos within the group! As her companions are defeated one by one, what will Carol do?