Worthless at Home, Whiz to the World: Volume 4

Saint Fam’s trial sends Noa and his party to the labyrinth city Velhen to retrieve the holy sword from the depths of the dungeon. Unfortunately for Noa, his oldest sister, Aeria, is the president of the trading company that controls the city, so he has to perform the impossible task of exploring the labyrinths without drawing attention to himself!
When Aeria’s all-seeing plan forces Raiza to drop out of the party, Noa has to earn his right to be an adventurer without the help of his Swordmaster sister. And so begins his conquest of unfamiliar labyrinths with only his adventurer comrades!