Next Sunday A.D., the world comes to an end. All we know of the even is that it's called the Bad Week, but, given the theme of the novel, it was likely to have been World War III. The only survivors live in the Habitable Zone, with various towns and gangs fighting each other.
Cross Agarwal is the son of a cobra farmer. Each morning, Cross has to milk the cobras for their venom, which the local warlord Kid-Stretcher Kyle uses to coat the arrow tips for his soldiers. One day, a white sphere descends from the sky, and three beings come out of it. They explain that they represent an alliance of peaceful beings (Explorers, Builders, and the Pile) and have decided to extend a hand of friendship to humanity, offering untold technological boons in exchange for some of the humans coming with them. Cross is one of the chosen. It's not long before they find out that the peaceful aliens need humans to fight a hostile species they call "the Killers", as their observations of humanity over many decades have shown that Humans Are Warriors (in fact, their name for humans is "the Worse Killers").
Thus begins humanity's rise from the ashes to joining an interstellar alliance, while trying to show the aliens that humans are good for more than killing.
The novel features examples of the following tropes:
- Abusive Parents: Rashid Agarwal is as far from an ideal good father as one can get. He exploits his kids and deliberately gave them all names (Burden, Cross, Albatross, Millstone, Anchor) to indicate that they're all a burden on him. He doesn't seem to care that first his wife and then his oldest son died while handling cobras.
- After the End: Earth is in a postapolyptic state after the Bad Week. Humans still endure in the Habitable Zone. Various towns and tribes fight one another for resources Mad Max-style.
- Alcubierre Drive: Based on the aliens' explanation of how they move through space, this is likely their method.
- Alien Abduction: The Explorers have observed humanity for decades and have even conducted up-close and personal studies of humans. They stopped when it turned out that humans aren't big on certain orifices being explored with probes, which is something the Explorers find highly unusual.
- Alien Invasion: Near the end of the novel, the Coward stages a takeover of all alliance ships and forces the Builders to create robotic suits for the Explorers to act as foot soldiers to attack and exterminate humanity. The suits themselves are remote-controlled because the Explorers are not fighters and would just use them to run away. The irony is that they're using weapons developed by humans to fight the Enemy. The only reason the humans aren't caught with their pants down is because one of the humans smuggled some of the Pile with her after the relations between humans and the alliance broke down.
- The Alliance: The alliance consists of three intelligent species. Since their names can't be rendered into any human language (in large part due to the three species not communicating using sounds), the aliens instead name themselves by their predominant trait: the Explorers, the Builders, and the Pile. It's quite a harmonious relationship between the three: the Explorers decide where to go, the Builders decide on how they will get there, and the Pile coordinates between them. They offer humans an eventual membership in the alliance.
- Annoying Younger Sibling: Cross's sister Albatross is never happy and is always complaining about something.
- Badass Preacher: The Madre believes in a warped version of Christianity and uses her personal inscribed bat to club "heretics" to death. She is very keen to learn that there's an intact copy of the Bible in Kylestown's church.
- Big Bad: The Coward eventually becomes the leader of the Killers/Enemy after all the warriors are killed by the humans. He then offers peace to the alliance and asks to join them peacefully. In their ignorance, they accept and unanimously vote to allow the Enemy join. The Coward then immediately vetoes the vote to let the humans join (all major alliance decisions have to be unanimous between the member species). Later on, he proposes that a member of his species join the crew of every alliance ship. Shortly after that, all alliance ships are taken over by the Enemy, and the Coward forces the Builders to create remote-controlled robotic suits for the Explorers to act as an army with which to wipe out humanity, using the very weapons designed by the humans.
- Bold Explorer: The Explorers evolved on a world where their survival depended on them looking around and discovering new things. Thus, not only are they amazing explorers and scientists, but they get something like a dopamine rush any time they learn something new. Una often uses it to play games with the Explorers, enjoying giving them "mental orgasms" by feeding them bits of information.
- Boulder Bludgeon: During the first battle with the Killers, rocks are all the humans are able to use as weapons, as they've either left their weapons aboard the ship or are unable to use them because they're inside their spacesuits. Later on, when they ask the Builders to make them weapons, the Builders insist that they will decide themselves on the type of weapons. What they come up with are... better rocks. An Explorer explains that the Builders have only witnessed humans fight that one time, whereas the Explorers have observed humanity for decades and know more about human weapons.
- Curb-Stomp Battle: The first battle between humans and the Killers results in the near-total slaughter of the more numerous Killers by the humans, with only a single casualty among the humans. This is because the Killers always try to fight one-on-one and only using fists and blades. Throwing heavy rocks or attacking all at once is something they consider to be dishonorable. They're also smaller and weaker than humans. A single punch from a large human is enough to shatter every bone in a Killer's body.
- Death World: According to the aliens, Earth is this compared to their own homeworlds. Unlike their planets, where resources are bountiful, and they never had to struggle to survive, Earth is full of dangerous life forms, and resources are fairly scarce, requiring constant competition and fighting among themselves to survive and prosper. When one of the humans points out that Earth used to be a lot nicer before the Bad Week, the aliens explain that they were talking about Earth as it was before humanity came to be. But, yes, humans made it even worse.
- Egopolis: Kid-Stretcher Kyle has renamed the town of Cake Creek to Kylestown after taking it over.
- The Engineer: The Builders evolved on a planet where getting to resources requires creative thinking and building things. Thus, this is what they're good at. Not only that, but building and perfecting machines is at the core of their religious beliefs. They believe that the universe is a giant machine. By building and perfecting machines, they become a part of the universe.
- Explain, Explain... Oh, Crap!: After the alliance votes to let the Enemy join them, they explain to the humans that all their decisions have to be unanimous to be fair to all member species. Cross realizes too late that the Coward is going to vote against humans joining the alliance, which is exactly what happens moments later.
- Full-Name Basis: The aliens always refer to humans by their full names.
- Heavy Worlder: Humans compared to the alliance races and the Killers/Enemy.
- Heroic Sacrifice: During the invasion, Kid-Stretcher Kyle has everyone in the town hide in his mansion. When the Kill Sat starts destroying it, he holds up the doorframe and makes his Number Two Franco get everyone out. Just as he stops supporting the doorframe, the building comes down on top of him. Franco says that Kyle died doing what he loved best: telling everyone what to do.
- Hilarious Outtakes: These are present at the end of the audiobook.
- Hive Mind: The Pile looks like, well, a pile of blue rocks. However, each "rock" is connected to every other part of the Pile using quantum entanglement. This means that the Pile is everywhere at once. The aliens use the Pile to communicate across light years and to get real-time information on distant planets. Each encounter suit contains a Pile "rock", which is used for communication. The Killers are the first to realize the benefit of having someone listen to the Pile's unfiltered stream in order to gain intelligence. The humans on Earth do that too. It's not until communicating with them that Cross assigns someone to listen to the Pile 24/7. Since they need to come up with battle plans and not have the Pile relay them to the Killers, Cross has the Builders set a room aside where the Pile has no access. While concealing information goes against everything the alliance stands for, they do recognize the importance of doing this.
- Honor Before Reason: This is how the Killers/Enemy fight. Their concept of honor requires that all fights be between two champions. It has to be an open fight with no weapons more complicated than a blade. Trickery and strategy are seen as dishonorable attempts at gaining advantage. Naturally, the first battle between some 200 humans and over 500 Killers is a Curb-Stomp Battle with humans slaughtering the Killers with only a single casualty on their side (and only because the man in question tried to talk to the Killers first). It also helps that humans are larger and physically tougher than the Killers (it's implied the Killers are from a lower-gravity world). The only Killer to try to find alternative means of fighting is the Coward, one of the weakest of the Killers. He comes up with new weapons and a plan, only to be ignored by the stronger Killers.
- Humans Are Warriors: The aliens note that humanity is the first civilization they encountered that didn't completely wipe itself out after discovering nuclear weapons. Only mostly. Also, the aliens' name for humans is "the Worse Killers" (the name "Killers" is already taken).
- I Am a Humanitarian: Meat Machine and the Famished have a reputation as cannibals. It turns out that they only ever ate one person and didn't like it. But they maintain their reputation in order to scare their enemies.
- Klingon Promotion: This is how the Killers advance in rank. The First is challenged by another Killer. If the other Killer manages to kill the First, then he becomes the First, and everyone below advances one rank higher. At the end of the novel, Cross reluctantly becomes the leader of the Enemy and keeps trying to get other humans to challenge him for the job. No one is dumb enough to do that because no one wants the job.
- The Leader: Steven Best is the first to try to make peace with the rival gangs and tribes aboard the ship, recognizing that humans needed to work together to survive. When the aliens select Best, Una, and Cross as the top three they consider to be leadership material, they ask them to choose one as the leader. Best tells everyone to huddle, and they do, which Una immediately recognizes as him having what it takes to lead. She then nominates her as his Number Two, much to Cross's chagrin. She explains that her position is the safest leadership position to have. Number Three is always blamed when things go wrong, and the leader is often plotted against. Meanwhile, those who plot against the leader often come to Number Two, assuming she wants to be on top. After Best is killed by a Killer, Una becomes leader, only to then immediately push Cross to the role of the leader, retaining her Number Two position. Despite some growing pains, Cross manages to show himself as a decent leader, even charging ahead of everyone at the Killers. When he contacts those left behind on Earth, his father chastises him for stepping up instead of shifting the responsibility to someone else. At the end of the novel, it's revealed that the humans have named the alliance's flagship The Best.
- Little Green Men: This is how the Explorers initially appear to humans. Except Cross quickly figures out that it's a suit. In fact, Explorers look only generally humanoid.
- Locked Out of the Loop: This ends up being the case with the Pile by the end, as various species start deliberately withholding information from it in order for it to remain a secret. The Pile eventually expresses its frustration and mild satisfaction with Cross suffering for it, as he was the one who started this practice.
- Meaningful Rename: After the first battle, Cross insists that they no longer call the Killers by that name. Instead, he suggests "the Enemy." The aliens accept.
- Missing Mom: Cross's mother died when he was eight. How? Well, she lived in a cave full of cobras, so the cause is obvious.
- Multi-Armed and Dangerous: The Killers have six limbs they can use as arms or legs.
- Poisoned Weapons: Each morning, Cross has to put on a cobra-proof suit and "milk" the cobras for their venom, which is done by going into the cage and having the cobras try to bite him. The suit collects the venom into special pouches. The venom is then taken to Kylestown, where Kid-Stretcher Kyle's warriors dip their crossbow arrows into it. The other tribes and gangs are angry at this, but they wouldn't mind getting their hands on Cross in order to get in on the action. The Southern Basin soldiers have guns, but they wouldn't mind dipping their bullets in cobra venom either.
- Reasonable Authority Figure:
- Kid-Stretcher Kyle turns out to be a pretty good leader. Despite all the tyranny, he seems to genuinely care about the town and its people. He ends up sacrificing his life to make sure everyone can make it out of his crumbling mansion during the invasion.
- Stephen Best is a natural choice for the leader of the humans in space, managing to get everyone to set aside their differences and work together. Until he decides to try to negotiate with the Killers and gets himself stabbed to death.
- Shout-Out: Best names an Explorer "Dora" and a Builder "Bob".
- Subspace Ansible: The Pile is used for instantaneous communication across light years.
- Translator Microbes: Translators are built into every suit the aliens use. They allow them to communicate among themselves, as well as with the humans. It's explained that none of the three species use sound for communication. The translators appear as holographic "faces" that speak and try to portray facial expressions. Translators can be set to "dumb down" an alien's words or make them "smarter".
- World War III: It's heavily implied that this is what "the Bad Week" was.
- Wrench Wench: Herk is pretty good at maintaining and fixing cars. She also manages to build her own bubble drive out of car parts, which proves to be key to allowing Cross and Una to get into orbit and stop the Coward's Kill Sat.
