The sun rises over a field in a futuristic Chicago. A rusty old ship rests on land, seemingly deserted for ages. Lake Michigan appears to be mostly dried up. We move to the rest of the area, where people are walking around wearing uniforms of identical colors to match their place of living. Beatrice Prior (Shailene Woodley) explains that after a great war, society was divided into five separate areas called factions to maintain order.
The Erudite faction is for the smartest and most logical-thinking people. They dress in a dark shade of blue.
The Amity faction is meant for the kind and peaceful. They grow crops and provide for other factions. They dress in orange and yellow.
The Candor faction values honesty, and they dress in black and white.
The most fearless go to the Dauntless faction. They are the protectors of the nation, and they are known for their bravery as much as they are known for their crazy behavior. Their uniforms are black.
Beatrice and her family reside in the Abnegation faction. They wear light grey clothes and are selfless and do not value power, giving them the nickname "Stiffs." They provide for the factionless, those who have no place to call home (basically the homeless population of the city). Because of this selfless demeanor, Abnegation forms the city's government. Beatrice's father Andrew (Tony Goldwyn) works closely with the Abnegation leader Marcus Eaton (Ray Stevenson). Her main concern is that she does not know where she really belongs.
Beatrice's mother Natalie (Ashley Judd) cuts her hair and only allows her a brief amount of time to see her reflection to avoid vanity. It is the day of Beatrice's aptitude test, along with her twin brother Caleb (Ansel Elgort), in which they will find out which faction they are best suited for. She asks her mother if she was nervous when she took her test. Natalie says 'No. I was terrified.'
Beatrice and Caleb go to the station where other 16-year-olds from the other factions are taking their aptitude tests. A Candor member, named Peter (Miles Teller), mocks the Abnegation kids and blames them for the dwindling supplies. Beatrice continues to wonder just where she will fit in. After the kids are all put through a brief history of the test and its origins, she gets up to take the test, monitored by a woman named Tori (Maggie Q). She puts Beatrice in a chair and has her drink a blue serum to start the test. Beatrice closes her eyes and then opens them to find herself alone, with Tori no longer standing by her side. She gets up and sees her reflection. She keeps turning her head and sees more and more reflections. Then there appears to be a rabid dog. It growls at Beatrice and then runs toward her. She closes her eyes and then sees it as a puppy. Her younger self appears, wanting to play with the puppy. It reverts to its mangy dog form, running to attack the little Beatrice. The older one runs after the dog, and they sink through the floor. Beatrice awakens with a jolt. Tori is in a panicked state. Beatrice asks her what the results were. Tori says they were inconclusive. According to the results, Beatrice is suited for Abnegation, but also Erudite and Dauntless. This is a rare case, known as Divergent; being suited for more than one faction. Tori tells her to go home and say she was sick from the serum.
When Beatrice gets home, she is hesitant to tell her family what her results were. She just says she got Abnegation again. Andrew says that he needs to resolve matters with Abnegation as there is trouble going on with the faction's helping of the factionless, as well as a rumor being spread that Marcus hit his own son. It's also hinted that Erudite wants to be the ruling faction, instead of Abnegation.
The day of the Choosing Ceremony arrives. The Prior kids meet the Erudite leader, Jeanine Matthews (Kate Winslet). It is suggested that someone in Erudite (most likely her) has been spreading the rumor about Marcus. Once the ceremony commences, the new initiates step up to a table with five bowls and a knife. They cut their hands and give a drop of blood into these bowls to choose their factions. Caleb chooses Erudite. There is scattered applause in Abnegation but the Erudite members proudly welcome him. Beatrice goes up, nervous. She cuts her hand and almost drops blood into Abnegation, but then decides on Dauntless. Her parents are surprised, and the Dauntless members welcome her. The initiates leave with their factions, and Beatrice looks at her mother one last time.
Beatrice arrives in the Dauntless faction with all the other initiates. They run wild, climbing to the top of the elevated train tracks and chasing after the train as it goes so they can hop onto it before it's too late. Beatrice meets a Candor initiative, named Christina (Zoe Kravitz). They then have to jump off the moving train onto a rooftop. Dauntless leader Eric (Jai Courtney) gathers everyone over the edge of the rooftop for them to jump into a hole. He asks for a volunteer to go first, and Beatrice steps forward. After some hesitation, she jumps into the hole and lands on a net. She is pulled out by Dauntless instructor Four (Theo James). He asks for her name, and she decides to call herself 'Tris'. When everybody else comes down, he leads the initiates to The Pit, where everybody is having fun and they get to eat. There, Tris meets an Erudite initiative named Will (Ben Lloyd-Hughes) and Christina's friend from Candor, Al (Christian Madsen). Another Dauntless leader, Max (Mekhi Phifer), comes out to greet the initiatives and welcome them to Dauntless. The initiatives, including Tris and Christina, get carried away proudly.
The initiates are given new all-black Dauntless clothing and set to begin training for them to prove they are worthy of staying in Dauntless. Eric warns them that if they fail to reach the top ranks, they will be kicked out of Dauntless and stay factionless, unable to return to their old homes. The first stage of training is combat where the initiatives fight against each other. Tris is put up against the last person to jump into the hole, a girl named Molly (Amy Newbold). Molly beats Tris easily. Additionally, she does not fare well in shooting practice or other tests. Four and Eric sneer at Tris and doubt her ability to keep up. To cheer her up, Christina, Will, and Al take her to a parlor to get tattoos. There, Tris finds Tori and follows her, even though it looks like she's trying to avoid her. She warns Tris that she shouldn't have chosen Dauntless as her new faction, because there are people looking for Divergents. She gives Tris a tattoo of three flying birds.
Tris practices fighting on a punching bag, with Four coming to watch. He tells her she's weak, but fast, and her moves won't work. He positions her properly and gives her tips on what moves she should use. Meanwhile, Christina is fighting Molly, getting beaten pretty badly. Christina is knocked to the floor and recoils from Molly, pleading for no more. Eric asks Christina if she wants to give up, and she says yes. He helps her on her feet and guides her somewhere. They walk over a bridge that stands over a deep chasm. Eric asks her if she's feeling better and then pushes her off the bridge. Christina grabs onto it for dear life, and Eric times her to make a choice - hang on and he will forget her cowardice, let go and die, or give up and force herself out of the faction. She almost slips off until the time is up, and she's still hanging on. Tris and Four pull her out as she cries. Eric reminds them that Dauntless cannot be afraid of anything nor can they ever give up.
The initiates then practice throwing knives at targets. Al throws his knife weakly and it doesn't hit anywhere close to the target. Eric tells him to go get it, but Al refuses to as everybody is throwing their knives. Eric stops everybody and forces Al to stand in front of the target. Before Eric throws his knife, Tris tells him that this won't prove anything. Eric makes her take Al's place. Four grabs four knives to throw. He throws the first one far away from Tris, but gets closer with each knife until he throws the last one close enough to cut Tris's ear. After the practice, she tells Four that he cut her, but he says Eric wouldn't have let her out of there if she was left without a scratch. The other initiatives, including Molly, congratulate Tris. Peter approaches her to congratulate her sarcastically while adding that there is a news report on both Tris and Caleb and their both choosing to leave Abnegation for other factions.
The next day, Jeanine and a couple of Erudite Council members go into Dauntless, as it is implied they are searching for the Divergents. Tris never reveals her status, but Jeanine tells her to let her know if she needs anything.
Tris is set up to fight against Peter. Four reminds her of the moves he told her about, which is to dodge her opponent's move and go for his throat first. Four also tells Tris that Peter always steps in before striking. Peter, being significantly bigger than Tris, has something of an upper hand, but Tris hits him in the throat as planned. However, he still ends up beating her hard, knocking her down, and then knocks her out with a stomp to the face.
When she wakes up, Tris sees Christina and Will standing by her side with black jackets. Will tells Tris she's been out for a day and that Eric has decided to cut her from the faction. Her friends leave to join the other Dauntless initiates on the moving train. Tris, not ready to be thrown out, runs after the train and hops on. Eric is slightly impressed by her determination and allows her to join in on their game. Both Eric and Four gather up members for their team in an extreme version of Capture The Flag, with everyone carrying guns full of darts that simulate the pain of a gunshot. They are all taken to an abandoned amusement park, are divided into two opposing sides, and Four's team tries to come up with strategies on taking the other team down. Tris appears to want to say something, but impatient with all the discussion she simply acts alone to get an idea of where their opponents' flag & forces are from a better, higher vantage point. So she begins to climb the huge Ferris Wheel. Four follows her, though he looks uneasy climbing up. Tris realizes that he's afraid of heights. They get their view on the other team and lead their team into an smart attack. Together, Tris and Four shoot through Peter and Eric, and Tris takes Molly down, and with Christina they gain the flag and emerge victorious. As part of a final Dauntless initiation, Tris joins the others on a crazy zipline over the city. She pulls the braking cable just before she hits the wall at the end of the line.
The next day, the Dauntless initiates are taking in bags of supplies from Amity and loading them onto trucks. Tris sees a light flashing in her eyes as if somebody is trying to get her attention. She walks behind the trucks and finds her mother had signaled. They hug. Natalie asks Tris if she really got Dauntless for her aptitude test. She admits her results were inconclusive. Natalie warns her not to let anybody know about this and to be safe, because Erudite is hunting down Divergents, believing they are a threat to their system since they do not conform to just one faction and are capable of free-thinking. Tris then asks Natalie if she was Dauntless. She leaves before answering.
Tris's ranking rises above the dreaded red line, keeping her right above Al. Her current position is #20. The next stage of training is a simulation room to test out the initiates' control of their fears. Molly walks out of the room, shaking and trembling. Four oversees Tris's test. As the simulation begins, Tris sees herself in a field outside a town, behind a fence near the Amity faction. A flock of crows fly over her and swoop down to attack Tris. She tries to run but gets stuck in mud. The crows surround her, but she tells herself "This isn't real," and she swims into what looks like a puddle but actually holds a larger body of water. Tris is snapped out of the simulation. Four asks her how she got out of there so quickly. She only lasted three minutes, quicker than most initiates. Tris says she just got into the water. Her second simulation has her coming up to her friends, but she is trapped by an invisible wall. Christina appears to laugh at her and then talks to Peter. Tris realizes she is in a tank that slowly fills up with water. It starts to fill up to the top until she is completely submerged. She sees her reflection and once again tells herself, "This isn't real." She taps the glass lightly, but it somehow causes a big crack before finally breaking completely. She wakes up from the simulation again, and Four once more questions how she got out of there so fast. He's noticeably suspicious, and tells Tris that no Dauntless has ever completed the simulation so quickly.
Tris goes to visit Tori. She reveals to Tris that her brother George was Divergent but he chose Dauntless as his faction. When he was found out, he was dropped into the chasm.
Tris goes to Erudite headquarters to visit Caleb. The other Erudite members look at her with surprise to see a Dauntless member in there. Tris tells Caleb that she thinks Erudite is planning to take over the other factions, starting with Abnegation. Caleb, now acting and thinking like a real Erudite, agrees, but maintains his devotion to his faction over his family ("faction over blood"). Tris tearfully leaves when she realizes her brother won't help her. She is stopped by two Erudite officials trying to take her in. She punches one of them and tries attacking the other when Jeanine stops them. She takes Tris into her office to refresh her. Jeanine reminds her of the need to maintain a balance in the system, as well as peace.
When Tris returns to Dauntless, she is caught by three masked guys. They carry her and nearly throw her into the chasm, but she fights herself out. She unmasks one of them, shocked to see it is Al. She fights them off and Four comes in to her rescue. He tends to her wounds, and she expresses disbelief that Al would attack her. Four says it's because he's trying to boost his ranks since he knows he's close to getting kicked out. Later, when everybody is eating in The Pit, Al tries to apologize to Tris for what he did. She tells him to leave her alone and that she'll kill him if he touches her. Afterwards, Tris and Christina come across the chasm where some Dauntless members are pulling out a body. It's Al, having jumped to his death out of guilt. Tris feels somewhat responsible for this. Tris admits to Four she isn't sure she'll pass her final testing either. When Four asks why, Tris says that Four knows she is Divergent. Four acknowledges that he knows, and says he's going to help her.
Four brings Tris into the simulation room where he lets her get inside his mind to show her his fears. They start off high above the city, simulating Four's fear of heights. Tris suggests they jump because it's not real, but Four says that's something a Divergent would do. They need to overcome their fears the way a Dauntless would. They walk carefully over to the tower nearby to continue. They become trapped inside a vent, simulating Four's fear of containment. The walls start closing in on the two of them. They discover some nails and wedge them into the wall-floor joint. This stops the walls from crushing them. Four's next fear has him being forced to execute a factionless girl, but he cannot look at her with his gun aimed at her. Only by looking away can he fire. Finally, he and Tris find themselves in Abnegation - Four's original faction. They're in a house. Coming down the stairs is Marcus, holding a belt. Tris realizes that Four is Marcus's son, Tobias Eaton. Marcus walks over with the belt to hit Four, but Tris fights him off, and the simulation ends. Tris and Four walk onto the balcony of his apartment. She realizes he is "Four" because of his four fears. He shows her the tattoos on his back. He has the symbols of each faction on his back. Four states that he doesn't want to belong to just one faction. He wants to be kind, fearless, honest, selfless, and intelligent. This hints that he, too, is Divergent. The two of them kiss.
Later, Four shows Tris a few Erudite members bringing in supplies. He shows her a vial of an orange serum that is being used to make people more prone to suggestion.
Tris's final test comes, with Jeanine and other Erudite members, along with the Dauntless members, watching her. She is sat down in a chair and is told that her hallucinations will be viewed on monitors. Her previous fears come back to her. She is almost attacked by crows again, but this time, she doesn't jump in the water. She sees the field catching fire and grabs a burning branch to scare off the birds. Tris suddenly finds that she's tied up and lashed to a stake among the burning field. She thrusts her bound wrists down so the fire burns the ropes, and then plunges her hands into the water as soon as she's free. Next, she is back in the glass tank that fills up with water. Instead of breaking the glass, she takes off her jacket and plugs the pipe that sends the water in. She then finds herself in Four's room. He goes to kiss her, but then gets aggressive. He throws her onto the bed as if to rape her, so she kicks him in the groin and throws him off. Tris appears to wake up from the simulation, hoping Four didn't see the last bit. Jeanine comes over to hand Tris a gun as her parents and Caleb walk in. Jeanine tells Tris that she knows what to do. Tris refuses, but then hesitantly aims the gun at somebody (we don't see who) and she pulls the trigger. This snaps her out of the simulation.
Tris is officially a Dauntless member. She and the other new members, including Will and Christina, are suited up and given guns as they line up for a mission. The Dauntless members are injected with a tracking device in case anybody gets lost, but Tris realizes they've actually been injected with the mind-control serum. As the Dauntless board the elevated train, Max and Eric see a man wandering out of line, uncertain of who to follow, leading them to realize he is a Divergent. Eric tells the man everything will be fine before he shoots him in the head. As the train carries the Dauntless, Tris very slowly and stealthily slips through the crowd until she is standing beside Four, and he takes hold of her hand. They are brought into the Abnegation neighborhood, ready to attack and round up the residents. The Dauntless members round up the Abnegation members, but Tris and Four refuse to join in the chaos. They are found out by Max and Eric, who conclude that both Tris and Four are Divergent. Eric aims his gun at Four, but Tris holds hers to Eric. Max aims at her, and Four aims at him. Tris and Four incapacitate both leaders and make a run for it, evading other antagonistic Dauntless members. They are then captured and brought to Jeanine. She recognizes Four as Tobias Eaton. He tries to attack her, but her guards hold him back. She has Four taken away while she orders Tris to be executed in a back alley. Before the villains can shoot her, they are shot by Natalie. She rescues her daughter, and Tris realizes that her mother was indeed a former Dauntless. They take their weapons to defend themselves. Will shoots at Tris and Natalie, and Tris has to kill him. She is upset that she had to do it, but her mother comforts her.
More Dauntless members appear to shoot at Tris and Natalie as they make a run for it. They fight back, but Natalie is shot in the side and quickly dies. Tris holds her mother and cries. She goes to find her father and Caleb in a safe house. She cries to her father, mourning Natalie's death. Caleb mourns as well, having left Erudite after realizing their corruption. Tris tells them that the serum Erudite gave the Dauntless members is controlling them into attacking the Abnegation members; part of a plot to usurp control of government from the Abnegation faction. To stop this, they must infiltrate the Dauntless fortress. Tris leads them away.
Tris guides Andrew and Caleb, and another fighter, to the train that takes them to Dauntless. They jump off the train onto the rooftop and down into the hole. Tris finds Peter and forces him to tell them where the fortress is after shooting him. The heroes encounter more controlled Dauntless members. Andrew shoots at them and kills them, but he is shot and also dies quickly. Caleb cries over his father, and Tris briefly mourns him as well. She continues moving until she finds the room with Jeanine and others, ready to complete the controlling of the Dauntless. all ready to kill many of the Abnegation members. Some of the Dauntless have already begun killing some Abnegation members off. Tris sees that Four has also been injected with the serum, controlling him to attack Tris. She fights back, but Four outfights her easily. Tris repeatedly tries to remind him who she is. She grabs a gun and points it at him, but then she turns it around to her own head. She continues to reassure Four, "It's okay, I love you." As Four takes hold of the handle of the gun, ready to kill Tris, she gently keeps his face turned toward her. This helps Four to fight back against the serum and throw off its effects. Four helps Tris fight off the villains. Jeanine tries to finish the process, but Tris throws a knife that pierces Jeanine's hand. Tris orders her to stop the process, and Jeanine refuses, saying she's willing to die for her cause. Four grabs a gun with a vial of the serum and puts it together. Jeanine snarls, "Guess you're not as Dauntless as you thought." Tris replies, "You're right. I'm Divergent." Four throws her the gun and she injects Jeanine with the suggestion serum, forcing her to release the Dauntless members from their control and then wipe the computer, erasing the program. After recovering from the serum and realizing what she'd been forced to do, Jeanine tries to attack Tris with her knife, but Tris knocks her out cold.
Four reunites with Marcus, his father, and he is obviously uneasy. Despite this, both Marcus and Caleb join Tris and Four as they board the train heading out of Dauntless. Tris is sad over the loss of her parents and she still doesn't know where she belongs. Four says he does know.
Tris narrates again, saying that they feel like the factionless, having lost their homes and loved ones. However, they will continue to fight if they must.
The film concludes as the train takes them outside the city wall to Amity.