Is It Wrong to Try to Pick Up Girls in a Dungeon' on the Side: Sword Oratoria, Vol. 2 (Light Novel), Paperback

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 connect to everything else. These events taking place above and below the surface will rock Orario to its core as the darkness lurking in the city bursts forth