As the Quasi-Bahamut Class Vessel Musashi passes over the hostile Sagarmatha Corridor and engages Stealth Mode, in the Murayama-Honda Manor, a young girl rushes off to her elementary class. At this time, a song is heard over at the Okutama Cemetery, and a high-spirited man starts his day. That same day, the girl, whose name is Masazumi Honda, is seen unconscious nearby the Blue Thunder snack shop.
Fortunately, she is helped by the girl named P-01s, who takes her to the safety of the snack shop. It turns out that she is starving, and the shopowner willingly gives her a meal to replenish herself. Masazumi explains that she is there as the Vice President of the Student Council to accompany the school's President Sakai to Mikawa's checkpoint, although visiting her mother's grave is also on her plans.
Seeing Masazumi's eagerness to be a politician makes the shopowner wonder about her choice of running for the second-highest position of the Student Council. Masazumi explains that she knows that someone who is native to Musashi will be better suited for the position of Student Council President, compared to her one-year stay in Musashi from Mikawa.
The shopowner then hands over a paper bag filled with snacks that Aoi and the neighborhood children would like. She then talks about Aoi's unusual habit of visiting the snack shop ever since she took in an amnesiac automaton a year ago. Masazumi is quite shocked at Aoi falling for an automaton like P-01s, and since it seems that the shopowner knows that Masazumi knows little about Aoi's struggles in the past, she suggests that she visit Remorse Way, so that she would know about what she is talking about.
Meanwhile, at Musashi Ariadust Academy, Teacher Makiko Oriotorai begins her lesson on Far Eastern History, which will cover the Harmonic Unification War, the event that caused the implementation of provisional rule over the Divine States.
Makiko decides to choose Suzu to explain part of the lesson, much to the blind girl's surprise, and she soon begins her lecture.
According to Suzu, there are the Divine States and the Harmonic Divine States, which exist on separate planes, with two separate groups of people living on each plane, and they live without turmoil for some time.
Toori soon interrupts the lesson, and it seems that he is more interested in the customer survey for the eroge Nurhaci than the lesson itself, much to Teacher Makiko's annoyance. Shirojiro is trying to quiet Toori down, but ironically he is also doing his own business; as Heidi goes to scold Shirojiro for working in the middle of class, Shirojiro is more surprised that he does not receive orders from Mikawa.
It turns out that except for a very small percentage of the class, no one is that interested to listen to the lecture.
With Suzu clearly struggling alone, Makiko decides to ask Tomo to help out; Suzu types out the text while Tomo reads aloud the words she types.
According to Suzu's text, the conflicts between the Divine States and the Harmonic Divine States began with the Nanboku-cho Wars. In 1412 TE, the instruments used to support the tectonic plates vanished, and the Harmonic Divine States collided with the Divine States, resulting in widespread damage. After the incident, the remaining parts of the Harmonic Divine States were relocated or merged with land from the Divine States. The merging caused the inhabitants of the Harmonic Divine States to populate the Divine States, and the inhabitants of the two lands waged war against each other as the people of the Harmonic Divine States blamed the Divine States for the loss of their home land. This is the Harmonic Unification War.
Makiko is impressed with the report Suzu and Tomo gave to the class, and Suzu heaves a sigh of relief.
Soon, Toori proposes a party all of a sudden and he asks for the perfect place to do it. Shirojiro instantly suggests a place that does not cost money, so Toori decides to hold it in the classroom. Toori then proposes to play truth-or-dare like last year, but Tomo is alarmed that it might just attract unwanted spirits in the process. Toori thinks that exorcizing spirits can be done later on, and asks Makiko's permission; surprisingly, she does not think that it's a bad idea and lets him slide. However, Makiko reminds Toori that he has to answer questions to save himself from punishment. And since he was not able to do so, and it automatically awards Toori a punishment, which for that month is: stripping in front of the class.
On the classroom next to 3-Plum, the teacher of 3-Bamboo, Mitsuki Sanyou, continues her lesson on Far Eastern History.
According to her lecture, after the Harmonic Unification War, the people who fell to Earth from the Heavens thought that there is a way to return to the Heavens without destroying themselves. It involves following humanity's footsteps, so that they would be able to return to the Heavens. Because of this, the book called the Testament is found, a history book about the old world.
Soon, Mitsuki hears the sound of "Strip! Strip! Strip!" from the other side, and she is clearly alarmed by the commotion.
Elsewhere, a man in a flambuoyant dress, accompanied by a girl with long black hair, make their way into the school. The man soon tells the girl, whose name is Azuma, about her uncelebrated return in spite of her status as the Emperor's son. Azuma is fine with the treatment, as she says that it is dictated by the Testament. Soon, they arrive at the doorstep of 3-Plum and the commotion is clearly heard from there.
Annoyed by the noise inside the classroom, the man, named Yoshinao, barges in, only to see Aoi Toori in all his naked glory for a moment. Fortunately, Makiko is able to close the door immediately. Soon, Makiko tries to explain herself to the new visitors and heads to another room.
Masazumi, with a bucket to wash the gravestone of her mother, sees P-01s in front of another grave. As P-01s talks to her brown algae friends, she observes that Masazumi has been taking care of her mother's grave. Masazumi tells P-01s that it marks the family grave, and she thinks that the idea of a family is probably unfamiliar to someone like P-01s, who is an artificial body with a soul installed to it. P-01s agrees, but does understand that Masazumi loves her mother.
Soon, P-01s sings the song that she likes to sing, and it immediately takes Masazumi to a time when she sings along to her mother as she sings that same song. P-01s finishes, and she notices that Masazumi is lost in her thoughts.
Masazumi eventually talks, and she tells P-01s about her painful past.
According to Masazumi, she belongs to the family of retainers of the Matsudaira Clan, with one family holding the military while the other takes over internal affairs. His father is supposed to inherit the position in internal affairs but was unable to do so, and as a result, she is forced to abandon her sexuality to uphold her family's name. However, due to some unexpected event, her path to becoming a male heir was interrupted, and her family was exiled from Mikawa, eventually reaching Musashi. She and her mother soon continued their lives in Musashi, until her mother was spirited away.
As Masazumi's eyes fill with tears, P-01s acknowledges her response to the question that has been in her mind for a while: why Masazumi wears a boy's uniform and whether she prefers male clothing or not. Masazumi is quite shocked at the automaton's response to her story, and the algae just calls foul of P-01s' statement.
Soon, upon leaving Sagarmatha Corridor, Musashi's Stealth Mode is disabled, and Masazumi and P-01s head over to the edge of the ship Okutama to have a view of the approaching territory of Mikawa. Soon, a ship bearing the insignia of the Matsudaira family flies next to Musashi, and Masazumi is greeted by the Lord of Mikawa, Motonobu Matsudaira. From everywhere in Musashi, Motonobu's face is shown, greeting everyone and expecting some nice fireworks on the way before moving on to Mikawa.
Musashi eventually reaches the special port alloted for Musashi in Mikawa at 12:32 PM.
In Musashi Ariadust War Trainee School, Toussaint holds the day's joint Student Council and Chancellor meeting, with the topic of "helping Aoi's bing confession go well".
Aoi starts the meeting by asking Tenzou if his experience for proposing to someone would be helpful; of course, Tenzou was insulted by his question, but he eventually gives out his tips. First of all, Tenzou suggests writing his love in a letter. Well, it turns out good at first, until Aoi's perverse thoughts of P-01s began to pour out of his mouth.
Tenzou is quite worried at how his letter would turn out, but Urukiaga notices that Aoi, a "breast connoisseur", hasn't mentioned P-01s' breasts yet. Well, since Aoi has not experienced P-01s' breasts first-hand, he can't describe it as well. As it turns out, everyone is disappointed at his proposed letter. Kimi decides to help out his "idiotic brother" by suggesting groping similarly-sized breasts to savor the experience, and it seems that Toori likes the proposition.
Soon, Neito and President Sakai arrive, with the latter asking Toori about his "dangerous" proposition to a girl. It seems that in spite of his perverse methods, Toori does love Horizon, and he is determined to confess his feelings for her. Hearing this, President Sakai heads to meet up with Masazumi before heading to Mikawa, leaving behind his support for Toori's proposal.
Kimi soon reminds Toori that he has an important dilemma to be settled, and the Aoi siblings decide on their next target: Neito Mitotsudaira. Kimi negotiates to Neito about Aoi's proposal, and surprisingly, Neito agrees to lend her chest for its success. Toori wastes no time as he places his hand on Neito's breasts, and a few seconds after her ordeal, she receives an embarrassing remark from Toori: "She's braless!"
In response, Neito (literally) singlehandedly threw Toori into the school building.
Meanwhile, in the highway to Checkpoint #2 of Kakamigahara in Mikawa, President Sakai notices the lack of people bringing out goods from Musashi. Masazumi thinks that the one-way flow of goods is a grim sign for Mikawa, but her thoughts are rejected by President Sakai.
Soon, a Jormungandr-level galley, the Eikoumaru, which contains Pope Innocent of K.P.A.Italia, flies at a far distance. President Sakai tells Masazumi that the Pope would oversee the development of the Loizmoi Oplo: the Mortal Sins' Armament, which consists of eight weapons that are capable to destroying entire cities.
Masazumi and President Sakai soon arrives at Checkpoint #2, and the two part ways. Before Masazumi returns to Musashi, she tells President Sakai that she has decided to investigate Remorse Way, a decision which the President commends. On her way back, Masazumi thinks about the current society she is in — where even people of power are still repressed by even higher powers. Then, she thinks about Toori and wonders if he too will be willing to risk everything to change the world.
Elsewhere, inside the Central Unification Reactor in Shin-Nagoya Castle that night, Motonobu Matsudaira prepares for his fireworks. Whether the kind of fireworks he has prepared is for celebration or for destruction remains to be seen.