The Journey to the Field of Fire (Episode 24)

The Journey to the Field of Fire is the twenty-fourth episode of the anime series.

Synopsis
Ginko visits a village to meet Yahagi, a Mushishi who believes she has discovered a new species of Mushi named Kagebi that takes the form of a strange weed. When Ginko learns that Yahagi plans to burn the weeds to protect the village, he attempts to interfere.

Plot
A woman spots a blue fireball floating through the sky. She follows it and sees some people gathering around a similar blue campfire. She wakes up and vomits up leaves; she believes this is punishment for a mistake she has made.

In the present Ginko visits a village where all the plant life is dry and crumbling. He asks two kids about a Mushishi that was rumored to be in town. They reveal that the Mushishi is named Yahagi and she is in the fields with some other villagers, they also tell him strange weeds have that kill the trees surrounding them have started growing.

The fields are infested with the weeds and the villagers plan to cut down all the trees around the village in the hopes that it will stop their growth. Ginko inspects one concludes they are a type of Mushi which he plans to investigate. However, Yahagi says the investigation is finished.

Back in the village Ginko mentions he has read Yahagi's reports before and expresses surprise that she is a young woman. He also assumes that her current research on the new Mushi is also good. Yahagi responds by saying there is no more need to investigate because they’re burning the whole mountain tomorrow. Ginko and the kids express surprise at the nuclear option, but Yahagi says it is required to protect everyone's lives. Ginko says he may be able to help and asks what has happened so far.

Two months ago, a volcanic rock was discovered in the fields; the next day there was a weed growing from a crack in the rock. Three days later, weeds had filled the fields and even after pulling them they continued to grow back. By the time Yahagi noticed a Mushi was involved, the weeds had begun emitting poison that killed the nearby plants. The mountain is currently infested with the weeds and they are encroaching on the village.

Ginko says that mountain is too much to sacrifice and since the type of Mushi is unknown they can’t predict the consequences. Ginko says to continue pulling weeds and wait, but Yahagi responds saying they won’t make it through the winter without crops. Ginko tells her she and the villagers are panicking and they should only risk their own lives rather than those of the entire mountain. Yahagi agrees but says that the villagers wouldn't understand. She resolves to protect her village without compromise. She leaves Ginko with her reports and tells him to leave.

Later the villagers are seen chopping down trees and Ginko confronts them, telling them they’re taking too drastic an action. The villagers respond by saying their families take priority. Ginko tells them they’re monkeys panicking and to use their heads. The villagers drag him away and they plan to set the forest ablaze that night.

Ginko wakes up in a locked shed, he sees through a window the villagers walking towards the mountain bearing torches. He realizes that because the weeds originally came from a volcanic rock, exposing them to fire would be a bad idea. He breaks out of the shed but is too slow to stop the villagers. The weeds and the mountain are set ablaze but when the fires recede, strange blue flames rise from the burnt weeds and float away. Ginko identifies the fireballs as "Kagebi." Yahagi also recognizes them and tells the people to not let the flames near the village, while doing so she breathes in one of the flames. Ginko and Yahagi order the villagers to close all their containers lest the Kagebi infest them.

Yahagi explains that in every Kagebi is a Mushi called a Hidane which feeds on human heat. The Hidane show up on cold days and slowly consume the body heat of  those who go near it believing it’s a real fire. On warm days they hide in containers. Yahagi says the village is likely already infected and warns the villagers to be wary around fires.

That evening, Yahagi expresses relief to Ginko that the Mushi is something they have seen before but Ginko tells her she is grasping at straws. He tells her the Kagebi are persistent and only she can deal with them. He tells her to send him a letter if she needs his help and he departs. As Ginko leaves, Yahagi shows symptoms of the Kagebi she swallowed.

Later a man is shown fishing in the cold and tries to start a fire; his flint doesn't spark but he spots a Kagebi nearby and believes it to be an ember. Back in the village Kagebi infests a family’s fire.

Yahagi visits the scorched mountain and concludes the weeds wont spawn anymore and the only problem remaining is the Kagebi. Upon returning to the village, she is made aware of villagers suffering from exposure to the Kagebi. She also begins coughing up leaves similar to those from the weeds.

Ginko returns to the village and Yahagi tells him seven people have died and more are sick after eating food cooked over Kagebi. Fortunately, things seem to have stabilized and most of the Hidane have been exterminated; however there remains the on that she had ingested. She reveals that when the Hidane consume enough heat, the weeds will be reborn. She plans to go somewhere that is deserted and die. She wants to leave the village to Ginko and for him to not make mistakes as she did. Ginko refuses saying the battle will not be over and her death won’t end it.

Ginko catches a Kagebi and hypothesizes that because Hidane feed on heat they are attracted to flames and are awakened from their weed-like larval stage when they are exposed to it, however if they come into contact with a Kagebi, a fake flame, the weeds will burn without awakening. The food cooked with a Kagebi will also have the same affect. Yahagi eats food cooked over the Kagabi and coughs up leaves that are burned; it appears Ginko was correct.

Later Yahagi and the kids inspect the mountain and it seems to be recovering. The Hidane seem to be gone, likely because it’s getting warmer. They see in the distance a Kabegi floating away, likely heading for a cooler place where it will wait for winter.