A room bathed in crimson red blood, the air choked with the smell of iron, and a shattered skull atop a dead adventurers corpse...
Thanks to Aiz and crew, the tumultuous events of Monsterphilia ended without incident, and they were finally able to relax-but only for a moment. Soon, they find themselves embroiled in a suspicious case of murder. As they begin to investigate, the ladies soon realize that they're getting involved with a killer that's more horrifying than they thought.
"What, is this...?"
In the midst of all this, they find a mysterious jewel that may...

Aiz Wallenstein, the Sword Princess, ventures into the deepest parts of the labyrinthine Dungeon beneath the city of Orario, vanquishing its monstrous denizens with the blazing light of her sword. But when she meets a certain white-haired boy, the encounter will forever change them both.