The Dungeon Anarchist's Cookbook

Carl, Princess Donut, Katia, Mongo, and Mordecai begin the fourth floor inside the Iron Tangle, a subway network whose repeated station numbers, colored lines, employee routes, monster cycles, and delayed stairwells form a large spatial puzzle. The group combines three personal spaces into a shared base and starts crowdsourcing route information from other crawlers. After Mordecai is temporarily removed for attacking the Prize Carousel host Chaco, Carl wins the Dungeon Anarchist's Cookbook. Escape Plan reveals that the apparently ordinary book contains inherited notes from earlier crawlers who tried to undermine the dungeon. Its hidden contents are invisible to viewers and showrunners but visible to the current System AI, and Carl will permanently lose access if he reveals what the book really is. He therefore studies it in secret and disguises Cookbook-derived ideas as his own work.

Carl uses derailment charges to force the Ochre Line engineer Gore-Gore out of his sealed engine car, obtaining an engineer key and learning that engine cars pass through an abyss portal after station 435 while ordinary employees use a separate memory-altering route. Information from Imani, Elle, and other crawlers also confirms that monsters travel every fifth stop for addictive race-specific drugs produced by Krakaren bosses. As rail failures spread, withdrawal creates increasingly dangerous mobs and leaves groups of crawlers stranded across the network. Carl, Donut, and Katia continue mapping employee routes, Station Repair, trainyards, and the abyss while Carl uses the Cookbook to improve explosives and engineering without exposing its existence.

Hekla and Brynhild's Daughters later ask the Royal Court to help rescue at least a thousand crawlers trapped near station 101. Katia voluntarily proposes reshaping herself into an armored cowcatcher for their captured Vermillion train, but Hekla secretly shoots her with phased bolts that hide their wounds, cause amnesia and bleeding, and are designed to disguise a later death. Donut discovers the attack and opens fire. Eva says Katia was being used to provoke Carl, then deliberately humiliates Katia until Katia activates Rush at Eva and accidentally kills Hekla instead. Katia receives Hekla's bounty and equipment, Eva survives, and Brynhild's Daughters begins to fracture. Silfa later supplies evidence consistent with Carl's belief that the confrontation was meant to create an excuse to kill him, but the complete plan remains Carl's reconstruction rather than a confirmed confession.

Despite the betrayal, Carl, Donut, and Katia continue the rescue effort. Using rapid-response maintenance carts, colored-line keys, conductor hats, and the repeatedly resurrecting gnoll Growler Gary, they build paired portal runs that clear blocked tracks and transport stranded crawlers to trainyards or safer routes. When one cart sequence fails and Carl accidentally sends a giant Station Mimic to trainyard E, he adapts by moving Bautista's group through the abyss portal instead. The combined rescues move just over 1,400 stranded crawlers toward places where they can still reach the stairwells. Meanwhile, stage-three withdrawal creatures begin releasing enormous numbers of Krakaren juveniles, soul-crystal-powered ghoul generators become increasingly unstable, and the floor approaches its final trap.

Mordecai recognizes the named train loops as the Syndicate logo and the larger Iron Tangle as a stylized map of historic worm paths. Katia's observation that the rail lines have paired opposite sides helps explain the missing geometry and the six enormous station mimics. When the floor's self-destruct sequence begins, hidden upside-down chambers open beneath the stairwell stations and Krakaren monsters pour into them. Carl suspends a rapid-response cart over station 36 so its portal sends the falling monsters directly to the abyss, while other crawler groups defend additional stations. After Elle confirms the paired geometry, Carl's attempt to reposition another portal cart carries him into trainyard E with a mantaur whose Grull summoning is about to complete.

The resulting Death Challenge reveals that Prince Maestro survived the previous floor and is sponsoring the level-250 war god Grull. Grull manifests through the mantaur, kills the Mimic Rex, and hunts Carl inside the sealed trainyard. Carl survives with invisibility and Mordecai's Special Brew while Elle and a Katia copy of Carl distract the god. Li Na, Li Jun, Donut, Mongo, and the others bring in a second living mantaur, trigger another Grull summoning, and send that vessel through the portal so the god is transferred into the abyss. Carl then sends the Nightmare Express through the same portal. Fire Brandy and Tizquick knowingly remain aboard and choose to die rather than continue their manufactured dungeon lives. The train's explosion contributes to further ghoul-generator failures, and Carl reaches level 41. In his next Cookbook entry, he explicitly recognizes NPCs and mobs as victims and commits himself not merely to surviving the crawl but to attacking the people and system that operate it.

After the fourth floor ends, Carl, Donut, and Katia appear in Odette's production trailer and meet Loita, who says Zev has been sent to a temporary reeducation retreat and takes over primary PR duties. Odette explains that Carl's Death Challenge became a gambling event, later admits that she personally sponsored Hekla, and begins warnings involving Eva and Chris that Loita censors before they are completed. Odette says paying viewers selected the fifth-floor theme and tells the group only that their crafting tables will matter. In a staging room, Donut randomly draws the Air Quadrant and the Dirigible Gnomes, whose objective is the Wasteland Fortress. A doorway opens onto a hot desert, but Carl, Donut, and Katia do not cross it before the book ends.