The Selection is now down to only 6 girls, with America spending more and more time with Maxon and everyone is under the impression that she is his favorite, including America. Maxon is getting frustrated with her though, wanting her to declare that she wants him completely so that the Selection can end and they can begin planning their life, but she just keeps telling him she needs time, as she's still trying to sort out her feelings between him and Aspen. Aspen keeps telling her that he will never stop fighting for her, but she's making it hard for him when Maxon gets all of her time and he only sees her in secret passing.
Maxon tells America he has a surprise for her, and takes her to a hidden room filled with books and a computer. He tells her his family are the only ones who know about this room and to keep it a secret. He looks up Halloween and shows her all the information he has on it (her previous question to him in book one when he told her he could answer any question about anything) and pulls a book out of one of the shelves and shows her a journal entry about a family getting ready for Halloween. He reveals to her that it is none other than General Illea's journal, and since he has to go he tells her that she can take it with her to read as long as it stays hidden and she doesn't show anyone.
Later on, Maxon tells her he's decided to throw a Halloween party since it ihasn't been celebrated in so long and that he is inviting all the girls families to visit them. America is ecstatic. She begins thinking through everything and realizes the thought of another girl with Maxon kills her, so she admits her feelings to him and tells him she couldn't be without him. Now he is the one who is ecstatic that she's finally revealed that she's not only there for the money for her family or some other reason, but because she loves him.
Her family shows up and she has a converation with her dad about Maxon. He asks her if she's happy and she says she is but that she's worried because she's found out that at the party one of the girls will be eliminated. He asks her why she thinks it could be her and she dodges the question, but she's noticed in the past week that he had made time for all the other girls and he never once came to see her again. Later, Marlee and America see Maxon walking in the gardens with America's father and talking. America asks if he's been talking to everyone's father but Marlee doesn't know. If he did, he didn't take the other fathers to the garden.
At the party, Maxon dances with all the other girls and completely ignores her, so she begins talking to Aspen and gets confused once again as she knows she still loves him. Maxon does eventually ask her to dance, and when he sees she's upset he apologizes and tells her he didn't realize she would see it as she did; that he was only spending time with the other girls in case she changed her mind about being with him to try to find a possible backup, but that it's only her for him, and he talked to her father for his permission to ask her to marry him and he was waiting until the morning and would announce the Selection had ended at that time. America goes to bed happy about what the future will hold.
The next morning, her handmaidens wake her up before the usual time and tell her she must get up and come downstairs. Unsure of what's happening since they won't tell her anything she does what they ask and she's placed in a black dress and taken to the grand foyer. All the other girls are there too except Marlee and America begins to get a sick feeling in her stomach, as she sees this will not be the happy announcement she expected this morning.
The palace doors are opened and the girls are paraded outside and onto a platform with seats for each of them. The whole city is there cheering for the girls. America tries to catch Maxon's eye but he purposefully ignores her.
Soon, America realizes what's going on when she sees one of the guards, Officer Carter Woodwark, a very kind man that she accidentally bumped into one day on her way to the restroom while in the Ladies parlor with Marlee, being led out in chains. The cries of the crowd turn from cheers to dismay. Marlee is led out behind Woodwark in chains also.
An announcement is made that they have been caught in a state of intimacy and that this crime is punishable by death, but that Maxon and the king have agreed to let them live but that they will receive 20 lashes and their status will be reduced to that of an 8. America realizes that this is what Marlee has been hiding from her all this time when she revealed she didn't want to win the Selection. It was because she's been in love with Carter this whole time.
When the lashings begin, America hears Carter comforting Marlee and telling her it will be over soon. They begin to whip Marlee across her hands until they are bloody pulps and America can't take it anymore. She screams for them to stop and tries to run to Marlee, but guards capture her and drag her back to her room. When Maxon finally comes to her, she tells him that although she understands he didn't have a choice, she doesn't think she can be a princess and have to watch something like that again. He begs her not to desert him, to give him time to fix it, and that things aren't always that way. She reluctantly agrees.
Later in the women's room, America is trying her best to hold it together although she misses Marlee and her family terribly and needs their advice (the parents were sent home after the beating had happened) when Celeste says that Marlee got what she deserved and is a whore. America finally beats the crap out of her and they are pulled apart and taken to the hospital wing to be patched up.
Aspen comes to see her once she's back in her room and consoles her for what has happened. He gives her a button from his guard suit and tells her that although he can't give her the things Maxon can, that he wants to at least give her some piece of him as a reminder that he's still there for her. She threads it onto a bracelet and wears it from that point on.
Celeste, being a brat as always, tells America to look at a magazine article she's found, and America knows it can't be good news if Celeste wants her to see it. The article talks about how girls are fighting within the palace now and America's outburst during Marlee's beating and it shows that America has dropped from one of the favorites to win all the way to last place.
Sylvia, an employee of the crown who has been teaching the girls school lessons and etiquette, reveals to the girls that foreign guests are coming to the palace and the girls will be split into two teams and will be required to plan the parties for the guests as a test to what they have learned. It is Celeste, Natalie, and Elise on one team and Kriss and America on another. America finds out from working so closely with Kriss that she and Maxon have been spending a lot of time together and America begins to wonder if he's moved on to her now that America has revealed she doesn't think she can be a princess. America likes Kriss and can tell Kriss really loves Maxon so she is even more torn with her feelings.
There is a rebel attack on the palace and America doesn't get inside from the gardens in time so she runs into the forest and hides in a tree. Two of the rebels come along and one of them drops the backpack she is carrying. America sees it is full of books. The girl looks up and sees America in the tree and America fears she will be killed, but the girl just smiles, bows, and runs away to catch up with the boy she's with.
The parties go great, but Kriss and America pull off the best one, and before the representatives from Spain leave, one of them named Nicoletta pulls America aside and tells her that she is with her and that if she becomes the princess to look her up as she feels they could make great changes together. America's heart swells as she finally has an ally in Nicoletta and of course her father even if no one else believes she can be a princess, herself included.
Maxon sends a note that he needs to see America and the other girls think that she's being kicked out, but Maxon takes her to the princess suite to show it to her and to give her a surprise. There is a hidden panel in one of the wardrobes and Marlee is inside. It turns out Maxon has kept Marlee and Carter at the palace the whole time and was trying to find the best time to let America see her without anyone finding out, especially his father since he knows he would be outraged. Marlee has been working in the kitchens and Maxon promises that he will sneak her out as much as he can to visit America. Marlee and Carter have gotten married and are living in a small home beyond the kitchen area.
Maxon and his father have to leave suddenly to go on a trip to New Asia because of a dispute there, so America and Aspen begin spending more and more time together. A project is given to the girls by Sylvia to come up with an idea for changing the country for the greater good. All the girls seem excited and America is too until she realizes she has no ideas that are feasible for what could be done to fix all the problems within the country and the world. She's seen the poverty firsthand and all the bad things that come along with it, but she can't think of a solution.
She begins reading the General's diary, hoping to get some ideas, and realizes this man who the whole world looks up to is nothing but a tyrant. He sells his daughter off to another royal so that he will be a king rather than just a president and has connived the whole time, not to find a way for the greater good of the country, but the best way to become powerful, and so this is when he establishes the caste system. He will place his enemies lowest on the caste scale so that their voices will be silenced for good and place those loyal to him higher on the scale.
As she begins to think about it, America realizes why the history they've been taught has never been taught from books. They've been told by everyone that "history is something you should just know, not something that has to be written down", and America sees that if it isn't written down, the truth isn't ever really out there and can be bent from generation to generation which is exactly what General Illea did. Those loyal to him developed the history that he was a hero and those in the lower castes, although they probably passed on the truth from generation to generation, were by that point looked down upon so much that even if they did tell the truth no one would listen and it would be seen as treason.
She goes to tell Maxon to find out if he knows what a monster Illea was and to tell him that she thinks the rebels have been looking for the diaries this whole time to try to show the world how Illea was. The guards to his room tell her he doesn't want to be disturbed and she starts to go back to her room, but one of the servants in the hall whispers to her that he isn't in his room and that they're rooting for her to win.
America goes through the palace trying to find him, and when she hears whispering and giggling around a corner she turns in shock to see Celeste with her body pinning Maxon to a wall and them kissing each other. Maxon looks up and sees her watching and turns to stone. She runs to her room angry and hurt, unable to believe what she saw since she's told him a thousand times what a horrible person Celeste is. She sees that although she thought she and Kriss were the frontrunners for being the princess she's been fooled the whole time. For someone to follow in the same footsteps of Illea and rule a country, they would have to have a princess content with keeping a country under their thumb which of course is exactly how Celeste is.
America tells Maxon she wants to leave, that she's done with everything. He refuses and tries to tell her that Celeste means nothing to him, but America won't hear it and demands to be sent home. He again refuses so she throws the bracelet at him that he gave her and tells him to leave and not come back to her room. Knowing that he won't kick her out, she tries to figure out a way to be kicked out and go out with a bang.
When it comes time for the girls presentation of their projects on the Capitol Report, America keeps hers a secret until the time comes, and then reveals on national tv that she thinks the caste system should be eliminated. She then pulls out General Illeas diary and starts to quote a passage from it and the king has the newsfeed cut. He demands to know where she got the diary and Maxon tells him he gave it to her to read when they were looking up items on Halloween. The king tells Maxon that America is to be kicked out immediately. Before the king leaves the room to go talk to Maxon, he tells Natalie that he has some bad news for her and that her sister was killed in a rebel attack that morning. In all the confusion and sadness in the room where everyone is comforting Natalie, America goes to her room to collect her things.
When she starts down the hallway Maxon is there and he tells her that although he wants change too, announcing it to the whole country was not the way to go. The changes have to be subtle or there will be riots and the country will never be pieced back together, plus since he isn't the king yet he can't do anything at the moment. In the midst of their conversation there is a surprise rebel attack and Maxon and America go to one of the servant safe rooms since they won't be able to get to the royal safe room in time. Maxon hails a guard and tells him to tell his family that he is safe and to find them when it's over. Once in the room, Maxon takes off his shirt and asks America to help him and she sees huge slashes on his back and scarring from previous beatings and realizes it's from his father. They talk and he tells her he became so close to Kriss after everything with Marlee because he was afraid he was losing her and he knew that he had to find someone else. After a while he began to realize what a sweet person she was and he admits to America that it's not like it is with her, it's more of a steady growth in is heart, but he does have feelings for Kriss too.
He tells her that although it's supposed to be his choice, his father has had his hand in the Selection this whole time, hence why Natalie and Celeste are still there. His father likes Celeste, and Natalie has no free will of her own so his dad knows she would be pliable when queen. The king doesn't like America since she is so strong willed, but was willing to let her stay since Maxon liked her as long as she didn't upset the balance. When she did, Maxon knew there was nothing he could do. America apologizes to him, not realizing what she did would cause his father to take out his anger on Maxon and that she didn't think through what she was doing fully, she was just so angry that she knew she wanted to leave. They reconcile even though they both know it's too late.
After waiting so long they realize the attack must be over and they leave the room. The guard who was supposed to tell the royal family that they were safe was killed in the attack and so they realize everyone has been searching frantically for them thinking them dead. America packs up her things to leave once the attack is over.
America is relieved to see that Aspen has survived the attack and tells him she's going home, but tells him that she needs time alone before trying to contact him. She admits that she loves Maxon, and although Aspen has told her he would wait for her, she doesn't want them to be together just because they are each others only options at the moment. He tells her there will never be anyone else for him and he will wait as long as it takes, the same way Maxon did when she came to the castle heartbroken over Aspen.
Before she leaves Maxon comes to her and tells her that his family is so overjoyed that he is alive that they have decided to allow America to stay if she wants to due to the fact that he told his dad America's quick thinking getting him to the servant's safe room is what saved his life. He also tells her that if she does stay, he knows that his father will still do anything in his power to get rid of her and asks if she's willing to accept that. He also tells her that she is the one who will now have to wait for him, as he's seen how she makes reckless decisions when she gets angry and he will still be spending time with Kriss to see how he feels about her. Knowing how much she loves him now she tells him that she will do anything she needs to.
When she starts to go back to her room the king corners her in the hallway and tells her that she is not queen material and that she shouldn't be content with her standing with Maxon as men are fickle and a single moment can change their hearts forever. She doesn't say anything but tells him that as long as Maxon wants her there she will be staying, and she vows in her heart that this will truly be a competition now. She will fight his father for Maxon, she will fight Maxon's feelings for Kriss, and she vows she will win his heart.