As the others go to pick up some supplies, Kanata spends the afternoon training with Rio. Just then, Kanata comes down with a fever, reminding Rio of when her mother fell ill. Out of medicine, Rio gets help from a priestess named Yumina, who diagnoses her with malaria and treats her. When Kanata wakes up, she explains she was overworking herself since she felt useless. She also mentions to Rio that she always wanted to play "Amazing Grace," having heard from a bugler she met when she was little. Rio then plays Amazing Grace from one of the tanks, explaining that a squad, much like a song, is composed of many different parts.

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.

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.