|That's right...it doesn't matter if I don't have a father. I'm a chosen Warrior, entrusted with the Armored Titan. I'll save everyone from the island devils and become a hero to the world.|
|— A young Reiner Braun finds hope for his mission|
While Gabi Braun and the Warrior candidates train, Zeke Yeager and his fellow Titans discuss Eldia's situation, and Zeke informs them that the Tybur family will use their status order to boost Eldia's reputation in the eyes of the world when the time comes to attack Paradis Island once again.
Afterward, Reiner Braun recalls his final days in Warrior training when he, Bertolt Hoover, Annie Leonhart, and Marcel Galliard were sent to Paradis Island to reclaim the Founding Titan. On their journey, Reiner learned that Marcel set up Reiner to inherit the Armored Titan instead of his brother. Reiner's shock was worsened when shortly afterward, a Titan consumed Marcel.
As they walk through the streets of Liberio's internment zone, Reiner and Gabi are greeted warmly by their fellow Eldians, who all praise Gabi for her accomplishments. Arriving at the gates of the internment zone, Reiner informs the Marleyan guards that they are on their way to the Warriors' headquarters. Reiner discusses the possibility of another war with one of the guards, and the other pesters Gabi for details about her role in the Marley Mid-East War, but is surprised when Gabi appears reluctant to talk about it. When Reiner asks her about her unusual behavior, Gabi accuses him of acting strangely, noting that his mother had also noted his strange behavior since his return from Paradis Island. Reiner attempts to explain away his behavior as a natural change that came with him growing older, but Gabi insists that he tell her the truth one day, noting that, should she receive the Armored Titan, she will receive all of his memories due to their blood connection.
Outside of the Warriors' headquarters, Udo and Zofia complain about being forced to wake up so early while Falco Grice trains, determined to surpass Gabi. Seeing her arrive with Reiner, Falco attempts to taunt her by claiming that he will inherit the Armor, but is silenced when she headbutts him.
Inside the headquarters, Galliard arrives for a meeting with the current Warriors, and is surprised to find Pieck Finger crawling on the ground, emulating her Cart Titan form. Entering Zeke's room, the two are greeted by Reiner, Zeke, and Colt Grice. Inviting them to sit down, Zeke informs them that they have been placed in a dire situation. Marley's use of the power of the Titans in their conflicts with opposing countries has led to foreign hatred for Eldians growing, to the point that it once was during the days of the Eldian Empire. To counteract this, Zeke informs the Warriors that they are going to have to devote themselves to Marley to prove that they have learned from their race's history. He also informs them, as evidenced during the battle at Fort Slava, that conventional weapons are slowly surpassing the Power of the Titans, and Eldians soon risk losing their strategic value for Marley. If this happens, Marley will soon be overtaken, and Eldians will risk losing their human rights and be placed in a life-or-death situation. The only solution, according to Zeke, is to retake the Founding Titan from Paradis Island, and use it to stabilize Marley's power, while at the same time crushing the people of Paradis Island, who pose a threat to the entire world.
Pieck points out that restoring the Founder will not restore Eldia's status in the eyes of the world, and Zeke explains that they will make the world aware of the danger posed by Paradis Island by having the Tybur family, holders of the War Hammer Titan, as their spokespersons. Having been the first family to join Marley against King Fritz in the Great Titan War, the Tyburs were given honorary Marleyan status in the Marley empire, and having never used their Titan in any of Marley's wars against foreign countries, the world will be much more likely listen to anything they have to say. Galliard is unhappy about using the Tyburs, complaining that they have never fulfilled their duty to protect Marley, and lead refined lives while their fellow Eldians are confined to internment zones, but Zeke and Reiner agree that working with them is necessary to bring Marley back into power. Zeke informs the Warriors that the Tyburs are currently holding a press conference to announce to the world that the Warriors will retake Paradis Island within a year, and that failure is no longer an option for them.
Elsewhere, the Marleyan commanders listen in on the Warriors' meeting. Although they note that Galliard seems unhappy with the plan, they agree that there was nothing wrong with what was said in the meeting, although Theo Magath is unhappy with the amount of information that Zeke revealed. After the meeting, Reiner watches the Warrior candidates train, and recalls more of his time as a candidate.
As the newly-chosen Warriors used their Titans in battle with an enemy nation, Marleyan officials observed from a safe distance. They observed the abilities of the Female, Armored, Jaw, Beast, Cart, and Colossus Titans, and one official admitted to nearly having some sympathy towards the inhabitants of Paradis Island, the future victims of the Colossus. Magath conceded that the new Warriors' abilities far surpassed those of the previous Warriors due to their rigorous training since childhood, but worried at the idea of entrusting children with retaking the Founder.
Later, Magath informed the Warriors that two of them, Zeke and Pieck, would be staying behind to protect Marley, while Reiner, Bertolt, Annie, and Marcel would be sent to Paradis Island. After the meeting, an enraged Galliard attacked Reiner, demanding to know what he did to get chosen as a Warrior. Reiner began taunting him, and Marcel was forced to drag Galliard away, stopping only to apologize to Reiner.
A parade was held for the four Warriors, during which Reiner spotted his father among the crowd. He followed the man to his kitchen. Reiner explained that, since he and his mother were now honorary Marleyans, they would be able to live together with his father. He was interrupted by his father, who demanded that he leave, angrily telling him that should Reiner's heritage be revealed, his entire family would be killed as a result.
On the day that the four Warriors departed for Paradis Island, Reiner said goodbye to his mother, who assured him that his father would be praying for his success. As their boat departed, Reiner vowed that he would use the power he had been entrusted with to exterminate the devils living on Paradis Island, and save the world.
Arriving at Paradis Island's borderline, Magath gave the Warriors some final instructions, telling them to head north after sunset. The Warriors departed during the night, but were soon forced to set up camp after their lights went out. Bertolt wondered whether it was true that the King of the Walls would not unleash the Founder, but Reiner implored him to believe in Marley's research. Marcel was similarly dejected, and Reiner began to worry that his comrades were having second thoughts about their mission, reminding them of all the harm the residents of Paradis Island brought to the world. Ignoring Reiner's words, Marcel apologized to him again, confusing Reiner. Marcel revealed that Galliard, not Reiner, was supposed to be chosen for the Armored Titan, and Reiner was only chosen after Marcel intervened, in order to keep his brother safe.
Reiner was left dumbfounded, to the point that he was unable to react when a Titan, awoken by the rising sun, rose up out of the ground and attacked him. He was only saved by Marcel, who pushed him out of the way and was grabbed by the Titan instead. As Marcel was devoured, the remaining Warriors fled, with Reiner vowing to punish the devils of Paradis Island and save the entire world.