"I don't want to lose any more of my family." Bell and Hestia are attacked by an escaped monster during Monster Philia. Bell fights to save the only family he has left, but is overwhlemed by the monster.

"Excuse me, are you looking for a supporter?" After his rapid growth, Bell reaches the 7th floor of the dungeon. He gets new equipment and is ready to go when a girl named Lilika approaches him. She is a supporter, and her job is to aide adventurers in the dungeon.

With Lili's help, Bell is progressing further into the dungeon than ever. Since he can focus on the fights, he can make more money. But Lili has a secret: she despises adventurers, and is waiting for a chance to trick Bell.

Bell defeats the minotaur and becomes the fastest adventurer to level up in history. After his success, Bell is given the nickname "Little Rookie." As he sets his sights on the middle floors of the dungeon, Ryuu tells him that if he wants to succeed, he's going to need a bigger party.

The Guild knows about Wiene. But instead of demanding answers, it assigns the Hestia Familia a mission they cannot refuse. Something awaits them in the dungeon’s darkness.

It was supposed to be the dawning of a new era. But selfish, evil men only care about what they can take for themselves, leaving others to face the consequences.

The surface is no longer safe for the Xenos. Now, the Hestia Familia must smuggle them back into the Dungeon. There’s just one problem: The Loki Familia stand in the way.