Eren Yeager introduces Mikasa Ackerman to Armin Arlert, who misunderstands their living arrangement. Armin thinks that because they are family now and sharing a room, that means that the two must be married.
Eren tells Armin that it is a complicated story, but he and Mikasa are now family. He promises to tell Armin the full story one day, not wanting to mention the murder of Mikasa's family in front her. However, Armin misunderstands and promises to support him.
When Armin asks if they are living together, Eren says they are sharing his room and that it is really cramped with the new bed. Eren means that the room is crowded with two beds inside, but Armin pictures a single large bed.
Eren then takes Armin aside to talk to him about how strong Mikasa is. He claims that she is a monster who will not let him up even if he submits. Eren is talking about a wrestling match, but Armin laughs, telling Mikasa that he sees she already has Eren whipped.
After Eren heads for the bathroom, Armin apologizes to Mikasa for having spoken so much to Eren instead of her. Mikasa is not bothered by that and asks Armin to tell her more stories about Eren next time. Armin agrees, but says he will save the best stories for their wedding.
Eren comes back and complains to Armin about how well Mikasa and his mother get along, because they will team up against him, but Armin says that it is good they get along so well. Some families fight when they start living together. Eren is surprised by that, but supposes his living situation is unusual.
Armin then heads home and says he will see the two lovebirds later, confusing Eren. Mikasa tells him not to worry about it and calls him "honey," which creeps him out.
Later, at the Yeager household, Armin stops by and meets with Carla, who tells him that Eren and Mikasa are not home at the moment. He says that is okay and that he has a gift to celebrate the marriage. Carla thanks him and goes inside to show Grisha the bottle of wine Armin has brought. She is surprised that Armin remembered their anniversary and Grisha mentions how Armin has always been such an observant boy.