Reborn as a demon lord in a fantasy world, Yuki is ready to play tourist with Lefi and Nell in Alfiro, investigating the mystery behind the attack on his territory all the while. But a surprise Undead outbreak clashes with his plans. He goes off to hunt the perpetrators, but is left with only more questions.

Later, Yuki returns to the dungeon with Lefi, where another surprise awaits—a good one this time! However, while he's busy making new weapons, learning new magics, and generally goofing around with his dungeon family, Nell returns with grim news: the prince of Alisia has staged a coup in the royal capital! How will our antihero of a demon lord handle these new political complications when all he wants to do is chill?!