Some of the characters from Ancestral Night make cameo appearances, but Machine isn't really a sequel. The story follows Dr. Jens, who enjoys her job on an interstellar ambulance crew dealing with a wide variety of medical emergencies. Some of these involve humans but there are so many species here that every call for help is a new challenge. The AI that runs the ship decides to take one last call before heading to the central system, the equivalent of jury duty in the US, and they find two ships locked together with the biological beings unconscious and the ship AIs confused and acting strangely. The take all of them back to Central Hospital and soon all sorts of things start happening in the usually boring station. Someone actually attacks them, the AIs forget things, and there are power failures for no reason, which could be deadly for the patients. But what Dr. Jens finds strangest of all is that there is a ward restricted to only a few personnel and no one knows who the patients are or what treatment they are receiving. Somehow it connects back to those two ships and the crippled AI, so Dr. Jens is determined to find answers.

Eight years in the making, the adventures of Xavier "X" Rodriguez finally come to a close, and despite the fact that this moment is clearly overdue, it is still bittersweet. Nicholas Sansbury Smith writes a lot of post apocalyptic fiction, and if you described each of his series to me, this is the one I would be the least interested in. When I reviewed the first book in this series I wrote "I found that I was able to put aside the improbability of it all and just enjoy the thrill ride. The characters were interesting, the scenario was unique, and I thought it had a good mix of grit, heroism, and despair. So if you want something different, but not too deep, then put on your radiation suit get ready to dive - The Hive needs you." So, now that we have reached the end of this thrill ride, does the finale deliver the ending this series so richly deserves?

They thought the planet was tidally locked to its sun, so they built mines on the dark side, and Nightside City to provide entertainment to the miners and part them from their hard earned pay. About a hundred years later, they realized it wasn't a tidal lock but rather an incredibly slow planetary rotation and suddenly the doomed Nightside City, with its showy casinos, became a popular tourist attraction. The lucky few got off-planet before the casinos realized their workforce was fleeing and they ensured only the wealthy escaped. P.I. Carlisle Hsing had hoped working for some of the larger casinos would be her ticket off-planet, but a rival framed her for some illegal hacking and she got blacklisted. Now she's stuck living and working in the part of town between the vibrant downtown and the abandoned sky scrapers up slope in the sun without the money to move further into the shade and forget about passage off-planet.

As the centuries go by, even Hadrian Marlowe is beginning to get old. His expertly crafted palatine genome, and the cryo sleep he has endured while traveling through space, can only extend his life so far, and Marlowe is now over 600 years old. It has been two centuries since he struck the emperor and fled imperial space to Jadd, leaving behind a war and political intrigue for the life of a fugitive. He has certainly enjoyed his time on Jadd, especially the last 40 years raising his daughter Cassandra. She is a skilled warrior who has learned swordplay from the famed Maeskoloi of Jadd, but she knows little of the dangers that exist beyond this planet. So when an Imperial messenger arrives with a pardon and calls Marlowe back into service in a war that humanity is losing, he has no desire to accept. But he must, because if he does not, there will be no future for any human, and that includes his Cassandra.

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.

Thanks to our favorite science fiction franchises we most frequently imagine alien intelligence to be humanoid, or at least an animal capable of communicating in some way. What humans find on the planet they call Pax is such a different life form that neither side truly understands what they are dealing with, and how they will both forever be altered by the relationship. To the colonists who fled a dying Earth with the idealistic intention to adapt themselves to their new environment, rather than the opposite, their new home looks like paradise. Pax has a breathable atmosphere, plenty of water, only slightly higher gravity than Earth norm, and abundant flora and fauna. Too late one of the colonists realizes that to the "plants" on this new world humans will only be tolerated based on what they can offer, and that they need to choose their new allies carefully if they wish to survive. Semiosis is a long tale of how each generation changes as they adapt to Pax and their evolving relationship with the photosynthesizing sentience known as Stevland.

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?