After recovering from his fight with Asterius, Bell learns from Hestia that he has reached level 4 and is warned by Fels that true peace between Orario and the Xenos can be only achieved after someone conquers the Dungeon's bottom level.
Bell's team reach the lower levels, and enter the 25th floor. Whilst fighting monsters and collecting materials they spot Luvis, a wounded elf adventurer who is attacked by a huge plant-like monster.
Bell discovers a mermaid called Marie who is a friend of the Xenos that Bell previously met. Despite Marie's warnings, Bell convinces her to guide him back so that he can rejoin the others and fight the Moss Huge.
Empowered by Haruhime's spell, Bell's party fights back the monster horde, until they realize that the Moss Huge's objective was to absorb the magic stones of the monsters they defeated, becoming much stronger.
The Gods hold a 'Denatus', a traditional meeting where they decide on adventurers' aliases. Hestia becomes upset by the interest the other gods take in Bell, who gets the alias 'Rabbit Foot'.
Cassandra has a disturbing premonitory dream. Turk identifies the culprit of the previous night's murder as Ryu, a former adventurer of the Astraea Familia, known as 'The Gale Wind'.
On the 25th floor of the Dungeon a monster appears and goes on a rampage. Jura brags about how five years before his familia, the Rudra, set a trap to eliminate the Astrea, Ryu's former familia.
Ryu runs to Bell's aid and then fights Juggernaut but she is defeated. The monster then attacks Bor's party, killing all save for Bor who manages to escape thanks to Ryu.
With retreat an impossibility, Bell's party fight for their lives when a Floor Boss spawns early. However, they are all adventurers; they will not die so easily.
The boss fight extracts a heavy toll on the party, and they must make a choice. If they go one way, they will live. But if they go the other? They will die.
The party narrowly survived, and now they must search for their missing friends. However, they're facing more than just monsters; they're fighting the Dungeon itself.
Bell and Ryu's relationship deepens as the trauma of the Deep Floors pushes them past their limits. They have each other, and that is the only reason they're both still alive.
The rescue party requested by Estia reaches Lili and the other adventurers. Under Lili's command, they prepare to go downstairs to rescue Bell and Ryu.
