For the past 100 years, the remains of the human population have been living in cities surrounded by walls. The walls protect humankind from giant humanlike creatures called titans.
After a century of peace behind the city walls. An unusually large Titan manages to break through the outer wall of Shiganshina District.
Eren Jaegar (main protagonist), a boy from this district witnesses
People flee to the inner walls for protection. The Shiganshina District of the outer most wall is overrun by Titans. While Eren Jaeger escapes by ship, the 'Maria Wall' is destroyed.
Eren Jaegar becomes a cadet. He has to pass maneuver training and prove that he can perform Multiaxial maneuvers.
This skill is necessary to use the equipment that is utilised in the fight against the titans.
Eren Jaeger graduates from the academy. While his squad is guarding the outer wall.
Eren Jaeger fights against the Titans for the first time.
Flashback of when Mikasa Ackerman and Eren Jaeger met for the first time.
The surviving squads, unable to climb out to the inner walls due to their maneuvering gears being low on gas, lose their fighting morale while the nearby supply depot becomes overrun by Titans. Mikasa learns from Armin that the 34th squad along with Eren died. Seemingly unfazed, Mikasa rallies the others to reclaim the supply depot and becoming inspired, they join her in the attack. Mikasa ends up running out of fuel and falls into an alleyway, leading Jean to assume command. However, he loses his nerve when he watches some of his comrades being eaten by the Titans. As a Titan approaches Mikasa, she at first accepts her fate but instinctively starts fighting back after remembering Eren's words of perseverance. As she prepares to attack with a small blade, another Titan appears behind her, and brutally kills the Titan in front of her much to her confusion. Armin and Connie show up, and they are all surprised to see not only the Rogue Titan fighting other Titans, but that it also shows knowledge of their weak points using hand-to-hand combat techniques while completely ignoring the humans. Armin gives Mikasa his gas tanks and blades so that she can go support everyone at the supply depot. Mikasa, however, refuses to leave him behind and ponders on the Rogue Titan's strange behavior.
With the supply depot area swarming with Titans, Armin has the idea of using the Rogue Titan to defeat them. Connie and Mikasa agree with his plan and defeat the Titans attacking it, before rushing there. Meanwhile, Jean and the others reach the supply depot despite suffering more casualties on the way, with Armin, Connie, and Mikasa arriving soon after. Armin's plan works, but while the Rogue Titan fights the enemies outside, seven smaller Titans lurk around the fuel storage area. With their gears out of fuel, Armin comes with another plan. The survivors draw the Titans' attention to an elevator and shoot them in the eyes to blind them, while seven of them will jump from the ceiling to finish them off. Connie and Sasha fail to kill their targets but are saved by Mikasa and Annie. Having successfully replenished their fuel, the soldiers prepare to retreat, but they see the Rogue Titan defeating all of the other Titans and falling down, and much to their shock, watch Eren emerging from its body. Mikasa reaches Eren and cries upon confirming that he is alive, while Armin notices that somehow his severed limbs had recovered as well.
The Recon Corps led by Captain Levi and his squad successfully retake a town from the Titans until they are called for an emergency at Trost as the Titans have invaded the city. When Eren was eaten and swallowed by the Titan, he found himself in its stomach along with bodies of its victims, some of whom were still alive. His anger over the Titans caused Eren to burst out of the Titan's stomach by transforming into a Titan himself and going on a rampage against them. When Eren regains his consciousness, to his confusion, he, Armin, and Mikasa are surrounded by the Army who are aiming their weapons at him. It is revealed that after Mikasa and the others saw Eren emerge out of the Rogue Titan, they all agreed to keep it a secret and bring him back inside Wall Rosé. However, Commander Kitz Weilman and his men did see it and have Eren cornered with Armin and Mikasa defending him. Kitz accuses Eren of being a Titan spy and demands to know what he is, but Eren has no idea since he has no memories of becoming a Titan or how his limbs grew back. Hoping to resolve the situation, Eren honestly answers he is human but a fearful Kitz orders the cannons to fire on them. As the three of them try to escape, Eren remembers his lost memories of his father giving him an injection, telling him to reclaim Wall Maria and go to their home's basement with his key. In order to protect Armin and Mikasa from the cannons, Eren partially transforms himself into the Rogue Titan.
After partially transforming himself into a Titan to protect Armin and Mikasa, Eren climbs out from the Titan to talk with Mikasa and Armin regarding the basement in his former house and how he believes that the secret to mankind's preservation and the key to destroying the Titans is located. Commander Kitz is still afraid and once again orders the cannon to be loaded. Eren comes up with two plans of escape: the first is for him to transform into a Titan and run away on his own, forever criminalizing himself in the eyes of humanity; The second is to have Armin convince to Kitz that Eren is an asset, not a danger. Armin has several flashbacks and comes to the realization that even if he is a coward physically, he can still defend his friends mentally and decides to help talk their way out of being executed. Armin tentatively convinces Kitz, only to have him overcome by fear and give the order to fire once more. But the order is halted when Commander Pixis and his men intervene, sparing their lives. In return, Pixis asks Eren if he will transform himself and help block gap in the wall to prevent further Titan invasions. He agrees, regardless of whether or not he is able to control his Titan form.
As Armin helps Pixis' subordinates coordinate a plan, morale among the troops begin to fade as some of them want to desert and be with their families. Pixis calms everyone by reminding them that if they abandon this chance to finally win against the Titans, they will be subjecting their families to their terror, which convinces the troops to stay. Claiming that Eren is the result of a secret project to turn humans into Titans, Pixis plans to have most of the troops gather at a far corner of Trost to lure most of the Titans away while Eren in Titan form carries the giant boulder to seal the hole. Along with Mikasa, Eren will be guarded during this mission by three of the best elites of the Garrison, Ian Dietrich, Rico Brzenska, and Mitabi Jarnach. As they head toward the giant boulder, Rico reminds Eren that many lives are at stake for the sake of this mission. Finally reaching the boulder, Eren transforms himself into a Titan, but suddenly attacks Mikasa.
Mikasa tries to reason with Titan-Eren, but to no avail. Titan-Eren continues his attack and accidentally incapacitates himself, slumping to the ground. The elites protecting Eren send up a red flare to signal that the plan has failed, much to the dismay of the troops observing from the wall. As Armin heads toward Eren to investigate, the elite squadron argues and eventually agrees to protect Eren over abandoning him, recognizing him as a valuable military asset. During the operation, Jean is separated from Connie and Annie after his Maneuver Gear malfunctions, forcing him to hide from two Titans in a building. Armin reaches the unconscious Titan-Eren, but Mikasa calls to him, warning that he is in a dangerous state. Armin plunges his sword into the side of Titan-Eren's neck, which briefly awakens him. As Armin talks of the outside world and Eren's promise to kill all the Titans, Eren leaves his dreamlike-state and regains consciousness.
Jean manages to acquire another Maneuver Gear from a dead soldier and escape thanks to Annie, Connie, and Marco distracting the Titans. With Titan-Eren now fully awake and carrying the boulder towards the gate as planned, Ian orders everyone to distract the Titans away from Eren at all costs, with some of them sacrificing their lives in the process. Eren finally blocks the open gate with the boulder, and a tearful Rico fires a yellow flare to signal that the operation was a success. As Armin tries to pull out Eren from his Titan body, they are surrounded by two Titans but are then saved by the timely arrival of Levi. With the gate finally sealed, the army eliminates all of the Titans remaining in Trost except two which are captured for research. As the army counts their casualties and dead, a shocked Jean finds Marco's dead and half-eaten body, Sasha's group is horrified to find a pile of corpses regurgitated from a Titan, and Annie mourns one of her dead comrades. Meanwhile, Eren is locked up in a cell guarded by the Military Police where he is visited by Levi and Commander Erwin Smith of the Recon Corps. After listening to his story and reasons for wanting the Titans dead, Levi allows Eren to join the Recon Corps under his command but warns if he ever betrays them or goes berserk again, he will personally kill him.
When word spreads about a Titan siding with humankind, the populace is divided over whether Eren is their savior or their end. Eren is brought to a military tribunal to be judged by the Commander-in-Chief of the military, Darius Zackley, who will decide whether Eren should be given to the Military Police or the Recon Corps, both of whom have their own reasons for wanting him. The Military Police want Eren killed as he is seen by them as a menace, while the Recon Corps want to use him to retake Wall Maria. As both sides get into heated arguments over Eren's Titan powers, one of the merchants siding with the Military Police accuses Mikasa of being a Titan as well, much to Eren's anger. When Eren calls out the Military Police and their supporters for their cowardice, one of them attempts to shoot him, only for Levi to beat Eren down. Despite being brutally beaten, he does not transform into a Titan, which Levi shows to the court that the Recon Corps can control Eren and proposes that he is to be made part of his squad. In the end, Zackley gives Eren to the Recon Corps where Erwin and Hange welcome him.
Levi and his Special Op Squad, composed of Petra Ral, Auruo Bossard, Erd Gin, and Gunther Schultz, who are all elites chosen by him, bring Eren to the old Recon Corps headquarters where Eren will learn to control his Titan's power under their watch. As Levi orders the castle to be cleaned, Petra assures Eren that despite his rude and harsh demeanor, Levi does care about the people under his command. Meanwhile, Erwin and Mike Zacharius discuss about the new recruits joining the Recon Corps and how they must prove Eren's usefulness to Military Command within a month. While discussing his powers with Levi's Squad, Hange arrives and asks Eren to help her in her experiments with the two Titans they have captured, which she names Sawney and Bean. Hange is revealed to have an obsession with Titans where she treats them like people despite the many times she puts herself in danger. In her talks with Eren, she reveals the Titans need sunlight to survive and despite their size, their bodies are disproportionately light. But the next day, the Recon Corps discovers Sawney and Bean have been killed. As Hange mourns for them, the Recon Corps deduce that the culprit is a soldier who escaped using their Maneuver Gear which makes Eren wonder who their true enemy is.
As the recruits are investigated over the killings of the Titans Sawney and Bean, Annie, who will be joining the Military Police later, gives advice to Armin and Connie that it is their choice to decide on which branch of the Army they join. The recruits are later greeted by Erwin who tells them the Recon Corps' next expedition within a month is to reclaim Shiganshina and find the secret hidden in Eren's home basement. After telling the recruits of the Recon Corps' fatalities in each expedition, Erwin tells the recruits that they may stay and join them or leave to join the other branches. As many recruits leave, Jean joins the Recon Corps in honor of Marco with others joining him as well including Mikasa, Armin, Sasha, Connie, Ymir, Krista, Reiner, and Bertholdt despite their fears. As the Recon Corps prepare themselves for the expedition, Eren is reunited with his friends and learns what happened to the others. Jean questions Eren if he can truly control his Titan powers as they are risking their lives for him. With everything ready, the Recon Corps begin their 57th Expedition beyond the walls.
During their expedition, the Recon Corps set up a formation where several scouts spread around the main group where they will report by flare gun if a Titan is nearby so the main group can steer to avoid them. After Armin's squad manages to kill an Abnormal Titan, a Titan with a feminine body, suddenly appears from the right flank at high speed. Much to Armin's shock, the Female Titan's body can withstand their blades and is intelligent enough to kill his seniors easily. The Female Titan captures Armin but after removing his hood and seeing his face, she leaves him alive and continues running. Armin is picked up by Reiner and Jean who reveals that their right flank was wiped out by the Titans, which makes Armin realize it was the Female Titan's work and she is possibly another Titan Shifter like Eren. When the three of them give conflicting sources on where Eren is in the formation, they realize the Female Titan's target is Eren and they must stop her. Despite their failed attempts to attack, she leaves them and heads to where Eren is: the center of the group.
Armin, Reiner and Jean are left stranded after their encounter with the Female Titan leaves them with only one horse, but are soon saved by Christa who arrives with extra horses. They wait for the order to withdraw, but to their surprise they discover their operation is continuing albeit heading in a different direction. Meanwhile, news reaches the center group about their right flank being annihilated by the Female Titan as the latter continues to wreak havoc within the formation. Soon the whole formation reaches the Forest of Giant Trees with only the center row entering it while the rest defend the forest from Titans. Eren realizes something is wrong when his squad has no idea what Erwin's orders are and what Levi is doing. As the Female Titan chases them at their heels, the squad desperately await Levi's command to attack but Levi instead tells his squad to cover their ears as he fires his flare gun.
Levi fires a noise round and tells the squad to keep moving forward. With more of the rearguard getting killed by the Female Titan, Eren begs his squad to let him fight but they tell him to trust Levi's decision. As he considers turning himself into his Titan form, Levi tells him to choose to be either a monster or a member of the Recon Corps. Eren starts remembering when Hange, Levi, and his squad had him try to transform into a Titan for experimental purposes but was unable to. During a break when he tried to pick up a teaspoon, Eren suddenly partially transformed, much to the squad's shock. They almost attacked him but Levi ordered them to stand down. Hange deduced that Eren is able to transform into a Titan not by solely injuring himself but also due to his desire to fulfill his goals. The squad apologized to Eren and told him they should trust each other. Remembering this, Eren decides to trust his squad's plan. It is then revealed that Levi's squad is bait to lure the Female Titan into an ambush where Erwin and his men fire hundreds of grappling hooks at the Titan, trapping it. Levi leaves his squad to meet up with Erwin to find out who the Female Titan is.
With the Female Titan restrained, Erwin and Levi try to figure out its identity with no success as it is able to harden its skin to prevent them from cutting out the human inside. Jean, Armin, and the rest of Levi's squad realize it was Erwin's plan to use Eren as bait to draw out the mole within the army who joined them after the Walls fell and only told his real plan to those who were part of the Recon Corps before the fall. Meanwhile, the others wonder about what is happening inside the forest until the Female Titan gives a loud scream that draws all Titans in the vicinity to her. Despite the Recon Corps' attempt to stop them, the Titans ignore the humans and eat the Female Titan's body in a frenzy, which makes Erwin call off the expedition. However, knowing that there is no confirmation that the mole has also been eaten by the Titans, Erwin orders Levi to regroup with his squad while the mole, disguised as a cloaked Recon Corps member, attacks Levi's Squad, killing Günther.
Erwin tells Hange that it was a mistake to think all humans who can transform into Titans are like Eren when the Female has unique abilities, while elsewhere the mole transforms into the Female Titan and chases after Levi's squad. Eren wants to transform into his Titan form, but the squad tells him to trust in their skills and keep moving forward. Petra, Erd, and Auruo manage to blind the Female Titan and attempt to cut off her arms and kill her. However, the Female Titan manages to quickly regenerate her right eye and kills Erd, Petra, and Auruo. Seeing his comrades dead, a grieving Eren transforms into his Titan form which gets Mikasa and Levi's attention. Believing his comrades and squad's death could have been avoided if he had transformed in the first place, Eren fights the Female Titan in a long battle. The Female Titan defeats Eren by decapitating the his head and swallowing Eren. Mikasa attempts to stop the Female Titan but to no avail. She is later joined by Levi who tells her to keep their distance, as the Female Titan is getting tired.
Levi orders Mikasa to distract the Female Titan so they can get Eren back. Levi launches a successful high-speed attack that debilitates the Female Titan but Mikasa almost gets kill when she tries to kill the Female Titan but is saved by Levi who breaks his leg in the process. They retreat with Eren's body, leaving the Female Titan badly wounded and slumped against a tree. As the Corps count their dead and retrieve their bodies before returning home, Erwin orders the dead they couldn't retrieve to be reported MIA. However, two Corps members, Dieter and his friend, against orders retrieve their dead friend Ivan's body which gets the attention of two Titans. As Mikasa kills one of the Titans to save Dieter who also loses his friend, the other Titan chase after the wagons containing their dead, which Levi reluctantly orders some of the bodies to be dispose to lighten the wagons load which includes Petra's body. Eren wakes up from his dream and finds himself and the Corps back at town. He almost gets angry when the people berate them until he sees a boy who admires them which send him into tears. A shocked Levi is questioned by Petra's father over his daughter's whereabouts while the people are enraged and upset at Erwin over the failure of the mission and the casualties that were sustained. As a result, Erwin and his subordinates are summoned to the capital where it is decided that Eren is to be handed over.
Annie has a dream of being trained by her father before waking up. In the Stohess District of Wall Sina, the Military Police are ordered to escort the Recon Corps convoy once they enter the capital. The Military Police are shown to be lazy and corrupt which one of Annie's colleagues, Hitch, reveals she join the police for that reason. Another colleague, Marlow, is disgusted, revealing he joined the police so he could reform it to become a better organization which Annie respects since he reminds her of Eren. After the convoy has entered Stohess, Annie is secretly called by Armin in the alleyways. Armin asks for her help as he is helping Eren escape the capital as the one riding in the convoy is actually Jean in disguise. She refuses at first but after Armin begs again, believing she is a good person, she finally agrees. Together with Annie, Mikasa and Eren, Armin leads them to an underground tunnel. However, Annie refuses to enter as she has noticed Armin is behaving strangely and there are hidden Recon Corps members watching her. Armin finally reveals he suspects Annie is the Female Titan since the Maneuver Gear she had after Sawney and Bean were killed is Marco's and Female Titan didn't kill him during the last expedition. Eren and Armin begs Annie to surrender as they want to help her but knowing her identity is exposed, laughs sadly and tries to transform. Despite the Corps attempts to stop her, she succeeds transforming using the spike in her ring.
Days before Eren is escorted to the capital, Erwin and Armin reveals to him they have a plan to capture the person they believe is the Female Titan and is shocked when they tell him it is Annie. Back in the present, Eren, Armin and Mikasa manage to escape a tunnel collapse while being hunted by the Female Titan. Eren tries to transform but is unable to which Mikasa suspects his feelings for Annie is preventing him. When another tunnel collapse traps Eren, Mikasa and Armin distract the Female Titan away from Eren. Meanwhile, Commander Nile Dok of the Military Police demands an explanation from Erwin on what is happening as his men hold him at gunpoint. As Mikasa and the rest of the Recon Corps distract and try to capture the Female Titan, Armin and Jean attempt to free Eren from the rubble. Armin tells Eren he has to fight Annie as anyone who refuses to sacrifice anything can never change anything. As Eren thinks about what Armin said, he remembers his hatred for the Titan who killed his mother. Eren finally transforms into the Rogue Titan and fights the Female Titan.
The Eren and Annie fight each other as Titans throughout Stohess, causing destruction and casualties while Hange orders her men to stand by before they capture Annie. Meanwhile, Erwin tells Nile he will accept responsibility for the damage his plan has caused, for which Nile has Erwin arrested while the Military Police help evacuate the civilians. As Eren gets more brutal with his attacks, Annie desperately fights him off and attempts to escape by climbing up Wall Sina. However, Mikasa cuts off Annie's Titan fingers, sending her falling. As Annie falls, she remembers her father asking for forgiveness, telling her to hate the world and ask her to promise him she will come back home. When it appears Eren is about to eat Annie, he stops once he sees her crying and her body starts encasing itself in ice. As Eren recuperates, he admits to Mikasa, Jean, and Armin that he allowed Annie to get herself frozen. As Jean and Armin wonder if sacrificing their humanity to defeat the Titans is worth the price, Erwin attends a government inquiry. Erwin reveals he kept his plans a secret to prevent leaks and despite the deaths and casualties of his plan and how they cannot get any information from Annie now that she is frozen, she is proof there are humans that can turn into Titans living within the walls and he plans to find and use them to launch a counterattack against the Titans. In the end, Erwin is acquitted, Eren stays with the Recon Corps, and Annie is put under the Corps custody. In the epilogue, a piece of Wall Sina falls, and inside of it is a very large Titan.