Early on in this series, Donut received a magical crown and of course she put it on before reading the description. The warning on the crown stated that the wearer would become a member of the Blood Sultanate and would not be able to leave the 9th floor of the dungeon without killing every other member of the Sultanate. This was a permanent liability as removing the crown does not negate the effect. She eventually replaced the crown, but that too was a mistake, because it allowed that same crown to be forcibly placed onto the head of fellow crawler Katia in a later book. At that point there was no way that both Donut and Katia could both reach the 10th floor, but it was a problem for another day. No longer. The 9th floor, known as Faction Wars, is finally here and it is one of the most deadly floors in the dungeon. Add on the Donut/Katia situation and there is no way that Carl makes it to the 10th floor without losing someone he loves.

The 7th floor of the dungeon was abruptly destroyed, so instead of the 7th floor this book takes place on the 8th, known as The Ghosts of Earth. Each team's leader must pick a location to start, and despite being well prepared for the Bahamas, Carl and Donut wind up in Cuba because Donut isn't exactly great at geography. Because no crawlers were eliminated on the aborted 7th floor, the AI has made the floor extra deadly in an attempt to dwindle down the number of crawlers before the 9th floor Faction Wars. This level requires the crawlers to collect monsters ala Pokemon in order to build out the decks they will use to combat other crawlers and NPCs in a real time version of Magic the Gathering. Of course, every part of this is done in a ridiculous over the top manner that culminates in an insane multiplayer card battle with everything at stake.

The sixth floor of the dungeon is identical in size and layout to the 3rd floor, but the same cities that were bustling with NPCs on floor 3 now lie in ruins and are infested with hundreds of years of overgrowth. This level is called The Hunting Grounds, and it features hunters that try to kill the crawlers in order to take their gear. The hunters use the gear to outfit their respective factions down on the 9th floor, and there are also freelancers that collect gear to sell to the highest bidder. The hunters all start at level 50, but they can kill NPC mobs to level up just like the crawlers do. After 17 days of hunting and killing each other, the level culminates in the Butcher's Masquerade, which is a party attended by the remaining hunters and the top 50 crawlers. What could possibly go wrong there?

Since Carl and Donut were able to overcome the complexity of the 4th floor by creating group chats that helped the crawlers share information, the AI that runs the world dungeon has responded by making some adjustments. The 5th floor is now a myriad of unique instanced zones (bubbles) and no new groups can be formed by the crawlers. The crawlers themselves will be evenly distributed across the bubbles, and since Carl and Donut are two of the highest level crawlers, that means they will be sharing their bubble with a bunch of I-can't-believe-these-idiots-are-still-alive n00bs. Each bubble has 4 quadrants within it (air, land, water, and subterranean) and each one has a challenge that must be overcome before the crawlers can move on to another one. Carl and Donut wind up starting in the air quadrant, which is good since cats and water don't mix, but that is just delaying the inevitable for Donut. Before Donut finds herself submerged, they first have to deal with the Dirigible Gnomes, who are using their insanely designed aircraft to bomb the hell out of camel like race that lives beneath them.

Carl and Donut are both on the newly introduced leader board, but like everything else in the dungeon, that comes with a downside. Everyone in the top 10 now has a bounty placed on their head encouraging the other crawlers to take them out via PvP. Of course, the leader board is just another way for the alien corporation running this apocalyptic game show to make money, and various sponsors now vie for the rights to each crawler. Carl and Donut both get sponsored, which opens up the possibility of sponsor and fan provided loot boxes, which they are both going to need. The 4th floor is known as the Iron Tangle, and it was clearly designed to disorient the crawlers. It is a mess of a multi train underground railway system with numerous tracks and junctions that intersect in an unpredictable way. Each group of crawlers arrives on the floor in a train filled with monsters, and more monsters get on and off the train each time it arrives at a new station. It makes you wonder what happens if the train gets to the end of the line?

Dungeon Crawler Carl covered the exploits of Carl and Donut as they barely managed to survive the first two levels of the world dungeon that now inhabits Earth. It also revealed the rules by which the dungeon operates and how the crawlers themselves progress and grow within it. It was established that the dungeon crawlers would get to pick their race and class when they reached the third level of the dungeon and that is exactly where this book starts. Yes, that's right, the crawlers will get to pick a race, which means most crawlers will no longer be human after their choice. The choices available to each crawler will differ based on the stats and skills they progressed on levels 1 and 2, which means a lot of specialization will be occurring. Both Carl and Donut have a myriad of choices available to them, but Donut absolutely plans to remain a cat, so her race choice is a foregone conclusion. Because why would a cat ever want to be anything else?

It's two in the morning, and Carl quickly puts his leather jacket on, along with his girlfriend's pink crocs sandals, just before running outside wearing only his boxers. He has no idea why her damn cat, Princess Donut, chose that moment to run out into the cold, but it's a show cat and worth more than Carl makes in a year, so he better go get it. That's when the world as we know it, comes to an end. An alien race has arrived and instantly destroyed every structure on the planet, transforming the destroyed matter into a worldwide, eighteen level dungeon full of monsters for an intergalactic game show. Everyone that was in a structure is already dead, and everyone outside now had a choice to make. Find a dungeon entrance within an hour and take their chances in the dungeon, or try to survive outside in a world with no structures remaining. It was way too cold for Carl and Donut to remain outside, especially the way Carl was dressed, which meant they had no choice at all.