Confronted by soldiers from the 9th Division, Aisha suffers serious injury in front of a frightened Noël. Meanwhile, Filicia takes Col. Hopkins hostage and orders his forces to leave the fortress as they barricade themselves inside. Col. Hopkins divulges his intention to use Aisha to instigate war, in addition to revealing his connection with Noël who once worked with him in reconstructing an ancient bioweapons technology that resulted in the deaths of many people. After being locked up in the distillery, he manages to make his escape in secret. While on tower patrol, Kanata hears a faint and distant signal for cease-fire prompting her to tell the others. Naomi with the support of the townspeople try to convince the 9th Division of the signal for cease-fire but are arrested by Col. Hopkins. Out of options and with an injured Aisha in tow, the girls decide to use the restored Takemikazuchi to stop the 9th Division and prevent all-out war between the nations.

Whilst on patrol in the snow, Kanata and Kureha stumble upon an unconscious Roman soldier. Noël seems to recognize her and asks to look over her. She wakes up the next day and introduces herself as Aisha Aldola, though she is unable to speak Helvetian. Kanata and Noël spend some time with her, and Kanata is surprised she knows how to play Amazing Grace. Later, Naomi and Yumina arrive, informing them that Helvetian armies are heading towards the fortress. Yumina acts as a translator for Aisha, who says that she wants to see the Angel Fossil (the one Kanata saw underwater in the first episode), the remains of the "Angel of the Apocalypse" that brought upon judgment to the world of the distant past.

Kanata asks Kureha to tell her more about Princess Iliya. Yumina asks Kanata and Rio to check up on an old woman named Jacott who lives in the mountains. The two later take a walk where Rio talks to Kanata about her half-sister. As the snow falls, Yacott, filled with memories about her love, runs off into the snow and never returns. Rio reveals she is the half-sister of Iliya, and decides to leave the fortress to help improve relations between the warring sides, leaving Kanata her trumpet.

Kanata and the others wonder if something is strange about Rio’s behaviour. As a typhoon settles in, Claus arrives with a package for Rio. After the others tell Kanata about Princess Iliya, they hear from Yumina that Seiya has gone missing and go into the city to search for him. Kureha and Claus find Mishio, who leads them to Seiya, who was trying to protect some eggplants. Whilst they manage to get Seiya to safety, Kureha and Claus are blocked off by a rockfall. It is revealed that Claus isn’t actually the infamous Desert Wolf that Kureha believed him to be. As the others send a wire over, the ground collapses beneath them, but Claus manages to rescue Kureha before she falls in. Despite knowing he is a fake, she still recognises Claus as the person she admires.

The squad are asked to watch over the emergency phone and wait for a call to check it is still in order, so Kanata decides to take responsibility whilst the others go out for various tasks. Before Rio leaves, she gives Kanata a trumpet book, signed by an Iliya Arkadia. Later, Seiya, Mishio and the Priest arrive, and decide to help Kanata practise using a phone, but a mess is made when Mishio spooks Shuko. Yumina arrives at that point, scolds the others and gives Kanata a change of clothes. Afterwards, Kanata needs the toilet but can’t leave her post, so she holds out until Rio comes back. The phone then rings and Rio answers, hearing a voice she’s not too fond of asking her to save Helvetia.

Everyone prepares for Fiesta des Lumiéres, which starts to bring bad memories for Filicia, whose comrades were killed in a fierce battle. While wandering in the battlefield with a heavily wounded arm, she falls into a tunnel which was well buried under the ruin of the past civilization, where she finds a corpse of a soldier of the old era. In her illusion, the corpse approaches her, apologise for the war they could not win, which makes life vanish from the sea, while on the ground humanity is falling apart. Then Filicia was rescued by someone named Princess Iliya. The girls later send off paper lanterns in the river and Filicia tells Rio her reason for living. Meanwhile, a priest seems to recognize Rio from somewhere.

The group give Kanata her paycheck early and she goes into town to spend it. In actuality, it is to get her out of the way whilst the others illegally trade some calvados to make some money. When they get word from Naomi that some investigators are planning to snoop in on the deal, they stage a mock shoot out to scare them off. Meanwhile, one of Yumina’s orphans, Mishio, runs off when she objects to having her hair brushed. Kanata finds her at the market, where she reveals she is looking for a certain box. Yumina explains to Kanata the box was a memento of Mishio’s mother that was taken when she died. Mishio ends up on a roof, but the noise from the mock shoot out causes her to slip. Kanata manages to save her before she falls, though it causes some rocks to fall that smash into the investigators’ car. While apologizing to Naomi, they notice the box Mishio had been looking for. Mishio decides to give it to Yumina as a symbol of how much she cares for her.

The squad take a "field trip" to the mountains where some observers need a maintenance check. Kanata, Kureha and Noël are forced to carry heavy backpacks on their hike up. Whilst they find the first observer quickly, the next one lies at the top of a mountain. They take a break at a running river but soon return to find their backsacks ravaged of their food and their compass. Despite the hunger, they eventually manage to find the remaining observers. At the last observer, Filicia shows the others signatures left by former members who had observed No Man’s Land from that point. They are then taken to a hot spring where Rio, who had fought against a boar to get some berries, awaits.