The Hidden Dungeon Only I Can Enter (Volume 3)

Noir is determined to enjoy his hard-won summer vacation. He has a new friend in a rival gild, a shop to open, and more levels of the hidden dungeon to explore. But with the thief known as the Phantom on the loose in town, Noir's peaceful days may soon be stolen. Worse, his best friend Emma may know something about the Phantom - something she doesn't want to tell Noir.