Akiyama warming up to "Hitori" and becoming the twins' first friend. While it is true that at this point in time, the twins are only interested in becoming friends with him so they can go to his house, it's still nice to see someone around their age being friendly to them after them having to deal with the other boyscouts.
When the twins find their old room at the Ichijou household, Migi starts crying because he misses their mom. While Dali initially tries to get him to stop because they could get caught, he eventually comforts his brother.
After the twins return from the Ichijou household, the Sonoyamas throw a party for Hitori and invite Akiyama over. Dali tells Migi that he should go on and enjoy the party while he goes to rest, claiming that he isn't hungry but Migi notices that his brother is starving due to having to live off of garbage and dog food. During the party, the Sonoyamas tell him that he can trust them and that he's allowed to share whatever's troubling him with them. He then fakes being sick so that he can run upstairs and swap places with a passed-out Dali to make sure his brother is cared for as well.
When Migi and Dali return to Origon Village after escaping from Reiko, they find out that she has framed Hitori for murder. They then decide to go to Akiyama for help who hugs Migi and is happy to see his friend again. After Akiyama leaves the room, Migi tells his brother who is currently hiding a closet that he doesn't have to hide anymore because they need to increase their allies and that Akiyama believes in them.
While Akiyama and Maruta are initially shocked when the twins reveal themselves, they hear them out and promise to keep their secret safe.
According to Reiko's story/flashback in the final arc, there was a time where she and Metry had a genuinely good relationship where she acted like a big sister to her and taught her how to do chores properly and embroider.
The series of flashbacks involving Metry watching Migi and Dali grow from infants to young children.
The twins convincing Eiji to live on so that all three of them can go home to the Sonoyamas and eat cherry pie together.
In the penultimate chapter, the Sonoyamas find out about Hitori's true identity. On Christmas, they get both of the twins presents and accept them with open arms. When Migi rushes to the closet to get Dali, his brother holds the door shut, possibly because he still fears getting rejected or because he doesn't know how to move on from this point. Migi manages to get Dali to open the door by saying that while it's true that both of them have changed and will probably become more different from this point on, there is still one thing that hasn't changed: That just as much his happiness is Dali's, Dali's happiness is his. The twins then reveal themselves and for the first time, all four of them eat at the dinner table as a family.
Later on, the Ichijous visit their house to celebrate Eiji's release from the juvenile detention center and it is shown that Maruta and Karen are still in love with each other despite their relationship being mostly long distance.
Following a small prank where Dali dresses up as Sali to surprise Eiji, everyone reconnects and laughs as the twins get into a minor scuffle where Migi jokingly says that he won't hand Sali over to anyone.
The three brothers visit Metry's grave where Eiji places a bouquet of flowers.
While Dali moves away to go to a specialist school in the end, Migi still believes that their hearts are one no matter how far apart they are.
The final episode of the anime was dedicated to the original author, Nami Sano, who had passed away just before airing due to cancer. Her tribute is just a small, handmade grave written entirely in French — not unlike the grave the twins made for their actual mother.
