This book begins with us learning about the world developed in the novel. What we know as the "Cloud" currently has grown and become self aware and humanity has named it the "Thunderhead". It has helped us develop a cure for death since it is all knowing, so everyone is now immortal. As people get older, they will go and be "reset" so that they look young again to whatever age they want, most choose their 30's, so although they look to be that age they can actually be hundreds of years old.
To prevent overpopulation, an organization called the Scythedom has been established to "glean" people, which is just a fancy word for killing them. There are hundreds if not thousands of Scythes in the Scythedom and all are regular people who have been trained by previous scythes and selected before the scythe council to continue the tradition.
Scythes are both feared and revered, with many people trying to buy extra time by offering indulgences such as cars, money, and homes. Most scythes do not accept these items (at least they aren't supposed to according to the scythe commandments) but some are not on the up and up and find loopholes to allow them to live lavish lifestyles (more on that later).
Citra is a teen girl who hears a knock at the door one day and it turns out to be a scythe. Although she and her family fears that one of them is about to be gleaned, the scythe is allowed in as a sign of respect. He proceeds to have dinner and chat with the family and then gets up to leave. Citra is angry that he didn't tell them he was going to glean their neighbor to begin with (a fact he has now revealed) and confronts him and he tells her that he could see her being a scythe but she tells him she would never want to be one, a fact to which he replies "that is the first requirement". After he comes back from the neighbors he gives her the knife he used and she trashes it once he leaves.
Rowan is a teen boy who just wants to get through his high school years and get out of his parents house since he feels he is the "lettuce". It's a metaphor likened to the fact that his younger and older siblings are the bread and meat of a burger but he is just lettuce, always forgotten. He and his friend Tyger coined the term in gradeschool.
One day he sees a scythe come to his school and he shows the scythe to the principal's office, where it turns out that the scythe is there to glean one of his classmates. When the classmate is called to the office, although Rowan only knows him by name and they're not friends he offers to stay with his classmate while it happens and the boy agrees because everyone else has already left to try to get away from the scythe for fear that they too might get gleaned.
Months later, both Rowan and Citra are sent an anonymous invite to an opera and when they both arrive the scythe is waiting for them. He reveals his name to be Scythe Faraday and tells them that they will now be his apprentices (all scythes train apprentices at some point when populations begin growing in the world) and that he is granting immunity to their families while they are within his care. Immunity is granted by a scythe by a person kissing the scythe's special ring which is then sent out to all other scythes so that they know the person has been granted said immunity.
Although neither of them want to be a scythe they don't have a choice in the matter and they leave their families to go live with Faraday. As he teaches them about what it takes to be a scythe (the types of killing they do, morals of scythedom, etc) they grow close to him and each other. Although a romance is forbidden for scythes, Rowan and Citra do kiss once since they are attracted to each other but both agree it won't ever go farther than that.
Scythes hold a meeting during each season to discuss political matters and so that apprentices can be tested. When Faraday takes them to the seasonal meeting their apprentice test is given by the "grande dame of death" named Scythe Curie.
She had been given this name because when she was first ordained as a scythe she gleaned the president and his whole cabinet and the story was spread far and wide and she never escaped the nickname (although she's not a bad person, which we find out later on).
Scythe Curie asks Citra what the worst thing she ever did was for her test and Citra lies and says that she tripped a girl down the stairs when she was younger and the girl broke her neck, but she had actually pushed that girl out in front of a bus to kill her. Citra doesn't want to admit that she did this though so she lies and Curie can tell and tells her she fails this test. Rowan then lies about his question too so that Citra doesn't have to feel ashamed that she failed. When they return to their seats Faraday tells him that was a mistake.
On a side note, when someone is killed in this world, since everyone is immortal that person is just taken to a revival center and brought back from the dead. Only scythes give out true death. Anytime someone kills themselves or anyone else they are considered to be "deadish" since they will no doubt be brought back to life soon. BUT, when a scythe decides it's their time to die and they glean themselves, this is irreversible according to the laws of the Thunderhead and the Scythedom.
After the end of the discussions of other scythe business, a scythe named Goddard addresses the high scythe Xenocrates (the head over all Scythedom) and says that he feels taking on two apprentices is unfair and it hasn't been done before, so he proposes that in order for the apprentices to not show favor to one another that as the first act of the chosen apprentice into Scythedom they be forced to glean the other one. Faraday protests but it's very clear that Xenocrates favors Goddard for some reason and he agrees.
That night, a knock comes at Faraday's door. Citra and Rowan answer it since Faraday is out on one of his late night walks and it is two guards who take them to Xenocrates home. Xenocrates tells them that Faraday has killed himself by jumping in front of a train. Citra and Rowan realize he's done this because he loves them both like his own children and by killing himself it meant they would be free of the scythe training obligation and could go back to their families.
It backfires on him though as Xenocrates says that only applies if no other scythe will agree to mentor them but Curie has agreed to take Citra as an apprentice and Goddard wants to take Rowan, so the death warrant still stands.
Citra grows very fond of Curie under her apprenticeship but feels that something is amiss about Faraday's death so she starts digging behind Curie's back to find out what happened to him and she learns that on the day of his death 3 witnesses at the train station were given immunity, so she realizes that those witnesses were bribed and that another scythe murdered Faraday. Judging from his reputation and the fact that they hated each other, she believes it to be Goddard.
Rowan has been training under Goddard and his 3 junior scythes (junior scythes are newly anointed scythes who live for a while with an older scythe to learn from them) for months at this point and has come to realize just how cruel Goddard is. He abides by the rules of Scythedom but just barely and he thrives on killing. When he and his junior scythes go kill, they do so in mass murders. They will sustain from killing for weeks (most scythes will kill a few people a week to meet their gleaning quota), but then they'll go wipe out whole buildings of people and Rowan can tell how much they enjoy it....except for one of the junior scythes named Volta. He and Rowan strike up a friendship and begin confiding in each other.
Volta fell under Goddard's spell as almost any young person would. Goddard knows just what to say and he always throws lavish parties, lives in a huge mansion that he claimed from a wealthy family (he got around the loophole of a scythe living modestly by having the man "donate" the mansion when in reality he threatened the man with gleaning if he didn't), drives fancy cars....pretty much everything the other scythes don't do. He calls it the new way of thinking versus being an "old guard" with "old ways". Since nothing he does falls outside Scythedom rules no one has been able to stop him and many others are joining his way of thinking.
Rowan finds out that the reason Goddard has such a hold over Xenocrates is that the young little girl staying with them that Goddard has kidnapped (he and his group gleaned a whole food court at a busy mall but "spared" the little girl and told her she was coming to live with them) is actually Xenocrates illegitimate daughter. Since scythes aren't supposed to have romantic relationships, if Goddard revealed this fact to the rest of the scythes Xenocrates would be gleaned due to breaking a scythe commandment, so Xenocrates does pretty much whatever Goddard wants in order to keep his place of power and avoid being gleaned.
Citra tells Curie about how she suspects foul play in the death of Faraday and Curie agrees. Two guards show up and take Citra to Xenocrates again while Curie is away. This time it's because she is being accused of murdering Faraday. They provide evidence in the form of her searches on the Thunderhead pertaining to the cameras at the train station. She had been searching through these to try to find video evidence that someone killed Faraday and had discovered that they were tampered with, but Xenocrates thinks she did it. With the extra evidence of a journal entry found in Faraday's nightstand when the other scythes searched his home after his death they've charged her with his murder. Xenocrates shows her the journal entry and it says something along the lines of "I fear for my life, I should have never taken her as an apprentice".
Citra knocks out the guards and runs and jumps off the top of the building and kills herself so that she will have a few days in the revival ward to try to get this sorted out. While dead, the Thunderhead talks to her and gives her the name of Faraday's murderer. The Thunderhead isn't allowed to interfere with Scythedom matters, but it tells her that since she's dead at the moment she's not under Scythedom jurisdiction so it can help her. It also tells her that she will have an important role to play in the Scythedom later on, whether she's alive or dead based on it's calculations.
Curie is there when Citra wakes up and tells her that she's taking her to a place in another country to a scythe friend's house so that she can hide until Curie can clear her name. Curie then tells her that the entry that was found in Faraday's journal was about Curie and not Citra.
Curie was his apprentice and she fell in love with him but he mistakenly thought that the way she was acting meant she was going to kill him. He had woken up one night to her inside his bedroom just standing there. It was because she was going to try to get into bed with him but when he woke up and saw her standing there she panicked and tried to lie and that's why he thought she was about to kill him.
She told him the truth later on and although he was flattered he didn't reciprocate her love until many years later and then they began a forbidden 7 year affair. When it was discovered by the Scythedom, they were such respected scythes at that point that instead of being gleaned or imprisoned they were sentenced to die 7 deaths, one for each year of their affair. After that they would only greet each other in passing and just associated as friends, although at this point in the story Citra sees the sadness in Curie's eyes and she knows that they must still love each other.
When Curie takes Citra to her friend's house the lady tells them that the Scythedom already has several scythes in search of Citra, so after resting a couple days to fully heal, Citra goes on the run with information from Curie about where to find Faraday's killer.
Citra arrives there and shoots the person in the knee from a distance to maim them so that she can force a confession but is shocked to find out that she actually shoots Faraday. He had faked his own death so that Citra and Rowan would be set free. Only Curie knew where he was. When Citra asks why Curie didn't tell her this, he tells her that the truth of what has happened could only reach him in person and he knows that's why Curie sent her; for protection until Citra's name was cleared and so that she could let him know that things didn't work out like they were supposed to and he was the only one who could help her finish her training while Curie is clearing Citra's name.
In the meantime, Goddard has said that they are going on one last gleaning before the winter meeting in the next few days, and he leads them to a Tonist church (the tonists are a group of people that believe immortality and the scythes aren't supposed to exist). Goddard leads them in and begins murdering all the people. Rowan is ordered to wait outside but Goddard tells him that "today is his day" and that he will be gleaning someone himself today. Rowan tries to reject this by saying it's not allowed as an apprentice but Goddard waves him off and says it will count as one of his gleanings. Rowan wanders over to the side of the church because although he wants to let people escape no one will run past him thinking that he's on Goddard's side. He finds Volta sobbing and when he asks what's wrong, Volta tells him that he went into one of the rooms thinking that only a couple people would be in there that he would have to kill but it turned out to be a room full of children. Rowan tells him that once he is a scythe they will go somewhere else away from Goddard but Volta says it's too late and that's when Rowan realizes Volta slit his wrists. When a scythe gleans themselves, they aren't revived, so Volta really is dead.
Rowan goes inside the church furious and finds Goddard tying up the church's high priest. Goddard tells him that he saved this man for Rowan, but when Goddard gives him a sword Rowan decapitates Goddard and also kills the other two junior scythes (they were evil too and tried to attack him after he killed Goddard).
Rowan sets the church on fire and goes out in Goddard's robes. Firemen are there to put the fire out but Rowan tells them that this is scythe business and they aren't allowed to interfere so they don't since they think he is a true scythe and not just an apprentice since he's in Goddard's robes and the church burns down.
Rowan is sent to Xenocrates and Rowan hints to him that he knows Esme (the little girl from the food court) is his daughter, so Xenocrates hints that if Rowan keeps it a secret, the investigation into Goddard's death will be dropped.
By this time, Citra's name has been cleared by Curie telling everyone about what had really happened and Citra is allowed to come back under Curie's apprenticeship.
At the Winter meeting, the apprentices are sent into a private room for their final test. They are told to kill the person sitting in the chair in front of them with the weapon of their choice that is laid out before them. Citra has to kill her little brother and Rowan has to kill his mom. The scythe judges assure them that their family members will be revived at the revival center right after they kill them, but this is their final test because if they can kill someone close to them then they do have what it takes to be a scythe.
Citra is mortified but does as she's told while comforting her brother. Rowan picks up a gun and shoots without a 2nd thought since he didn't care for his family very much anyways, and the fact that he did it so easily makes him wonder if he's more like Goddard than he would care to admit.
Citra is declared as the winner of the contest and is announced in front of everyone as a scythe. When asked what she wants her new scythe name to be (they always take new names from the Age of Mortality saints when they become junior scythes), she tells Xenocrates that it will be Scythe Anastasia Romanov.
When Xenocrates says that's not an appropriate choice because Anastasia never accomplished anything of note in her life, Citra tells him that she was the product of a corrupt system, and that if she hadn't been, who knows what might have become of her. Citra says that she will be another change that might have been (hinting at taking down this corrupt Scythedom) and so she will be known as Anastasia.
She is told to kill Rowan per the previous arrangement after this, but she's already thought this through and she punches him hard enough to make him bleed and tells him "I will glean you, but that's for breaking my neck before!" (at the Autumn meeting during their previous apprenticeship competition he broke her neck so that he'd be disqualified and she would win, since he wanted her to be a scythe and not him so that he didn't have to kill her). This transfers blood onto the scythe ring, aka his DNA, so he has been granted immunity.
When she pulls out her blade to "attack" him, the ring glows red along with the surrounding scythe's rings, so they yell out for her to stop and that she can't kill him. She feigns ignorance and tells them she didn't mean to give him immunity when she punched him. While the Scythedom debates what to do with him for the year that he's immune, Citra leans close and tells him there's a car waiting on him outside. He makes a run for it and it turns out that it's Faraday in the getaway car.
In the Epilogue, it's revealed as an excerpt in Citra's journal that someone is out there taking down corrupt and evil scythes by fire and has been dubbed "Scythe Lucifer". She says that if he ever comes her way she hopes he'll see her as one of the good ones, "the way he once did". END OF BOOK 1