Carl, Donut, and Katia arrive on the fifth floor, called the Bubbles, just after the fourth floor collapses. Carl immediately receives an achievement for entering as a top-ranked crawler, but the reward comes with a dangerous penalty: all current and future bounties on him are doubled. The group emerges in an Air Quadrant during a brutal sandstorm, learns that only 178,887 crawlers remain, and contacts Mordecai through chat. While they struggle toward shelter, Donut is forced to choose a new class and, after Mordecai talks her through the options, she picks Glass Cannon; because of her Character Actor limitation, she gains most of the class benefits but misses the crucial constitution increase.

As they cross the storm-blasted landscape, Carl notices that their area is shaped like a giant bowl and that visibility is almost nonexistent. The group finds a sloping entrance into a tunnel system, but a magical barrier blocks entry with a warning that they cannot enter another quadrant until their current quadrant’s castle is liberated. Carl tests the passage with a banger sphere, which triggers a trap in the dark tunnel below, confirming the subterranean zone is both separate and dangerous. Realizing they must stay in the Air Quadrant, the group continues toward a nearby town.

They reach a fortified settlement called Hump Town, where a giant camel-like Dromedarian guard named Clay lets them in after Carl pays a toll with a blitz stick. Clay explains little, but the group quickly learns the settlement is a brothel town and is warned to stay out of city hall. That warning instantly becomes a quest to investigate city hall, signaling that the forbidden building is likely important. Once inside, the storm ends, the town’s retractable fabric awnings are rolled away, and Carl sees the full scale of the area: the settlement sits inside a massive dome atop the Necropolis of Anser.

Mordecai soon meets them in his new temporary body, a skyfowl much closer to his real form, though he is annoyed that it is a clipped cleric body with limited flight. He explains that the fifth floor consists of many dome-like bubbles divided into four quadrants: Air, Land, Sea, and Subterranean. As the group walks to an inn called The Toe, Carl notices other crawlers keeping their distance and begins to understand that this floor will force cooperation with whatever weak survivors share their bubble.

At the inn, an announcement lays out the floor’s rules. Each bubble contains four castles, one per quadrant, and each castle has a stairwell in its throne room; however, the stairwell will not open until all four castles in the same bubble are conquered. After taking their own quadrant’s castle, crawlers can move into the other quadrants to help, and only when all four castles fall is the bubble “popped.” Mordecai points out their immediate problem: the Air Quadrant castle is far overhead near the dome ceiling, and the bubble likely contains too few capable crawlers to clear four castles in time, so the group must rest, open their accumulated boxes, and begin planning at once.