Kyoko Byakuya discovers a village at the foot of Mount Sengoku, an old volcano that hasn't been active in a long time. The volcano has produced golden hair-like fibers, more human than geological, and the villagers worship the hair as a blessing. The hair, which they call amagami, gives them blissful extrasensory powers, but the volcano erupts, giving them a vision of a dark god, and Kyoko Byakuya is the only survivor, her hair transformed into amagami. Strangely, the village has been destroyed for more than sixty years...
Later, struggling reporter Wataro Tsuchiyado discovers Byakuya, and through the subsequent chapters and horrors, tries to keep track of her and discover what has been going on.
Provides examples of:
- Ascend to a Higher Plane of Existence: The villagers believe that after his supposed death Father Miguel actually returned to the heavens. They're right. He also had some assistance, with Kyoko's help.
- Bandaged Face: Kagero Aido is the lone survivor of his cult, but has been disfigured by the Akashic records crushing him, and wears bandages over his face when he's seen again.
- The Bad Guy Wins: Mostly subverted. While Kagero does manage to become an Eldritch Abomination, Kyoko and Miguel become another god who he can never defeat and who will eventually overcome him.
- Because Destiny Says So: Father Miguel accepts his execution because it was foretold to him. He urges his brethren to leave him so they have a chance to live. The reason is that he needs to die to help Kyoko take on Aido.
- Bittersweet Ending: While Kyoko and Father Miguel use their powers to fight the thing that Aido becomes, Kyoko thanks to this loses her humanity. She sends Wataro's consciousness back to the present after thanking him for all his attempts to help her. Wataro comes back to a sea of corpses— the tied-up cult victims that helped Koyko in her journey — as well as the traumatized cultists that can't handle the information. Dr. Kurodera is alive, however, and it's implied he and Wataro's bond will help them recover from the experience. Wataro also knows that Kyoko is now a god, a beacon of hope that is fighting Aido in the stars, and she will eventually win.
- Blessed with Suck: Kyoko Byakuya's wealth of information from her excess of amagami proves deleterious to her mental state, tormenting her with an endless flow of knowledge that is sometimes traumatic and horrifying to her. It also makes her a MacGuffin Girl to the Big Bad, until she finally gains controls of her power in the climax.
- Body Motifs: Brain imagery is featured prominently. The Akashic records are presented as a brain-textured cloud of matter, and Yukio Kurodera's obsession with Kyoko makes him dissolve into an abstract neuron mass.
- Church of Saint Genericus: The inhabitants of Kiyokami Village are persecuted Christians, though their tradition or denomination is never specified. They were all slaughtered via crucifixion in the past.
- Climactic Volcano Backdrop: Mount Sengoku is central to the story, being the place where Father Miguel was executed by being pushed in, and from which the mystical hair fibers in the story originate and empower people to see the truths of the universe.
- Commonality Connection: Dr. Kurodera agreed to treat Kyoko on seeing that she had the same amigami hair as natives in his village. His son also started bonding with her while performing hypnotherapy.
- Cool Old Guy: Dr. Kurodera is old enough to be Kyoko or Wataro's father, and he had a college-age son. When the cultists kidnap him, Wataro, and the people whom Kyoko met, he pleads with them not to unleash the power of the stars. It's not for his sake but rather theirs. As the mass meditation starts, he resists through sheer Heroic Willpower.
- Creepy Blue Eyes: Beniko Yamaoka has very unsettling-looking eyes which, in the art on the inside of the slip cover for the print edition that shows all the main characters, are a vibrant blue.
- Decoy Protagonist: Kyoko Byakuya is the point-of-view character for the first chapter, but after her changes from the amagami, she becomes more of a driving figure in other people's lives, with Wataro Tsuchiyado becoming the point-of-view character as he tries to investigate her story.
- Driven to Suicide: One location in the story is a cliff known for suicides, so a family has set up an inn nearby to talk people down. The area is also plagued by hideous insects that jump under people's feet and resemble the bodies of previous suicide victims when squashed. Wataro Tsuchiyado gets a vision of Kyoko throwing herself off the cliff and goes to find her, but when it comes to pass, she does so to lead the suicide bugs off the cliff with her, and she survives the incident.
- The Dulcinea Effect: Wataro at first pursues Kyoko for a selfish reason, to do a profile on her and get a scooop. Then when he sees a cult kidnapping her and using her, he takes the next opportunity to free Kyoko. His quest soon becomes to track her down for answers and to make sure that she is safe. Kyoko sincerely thanks Wataro for trying to protect her before merging with Father Miguel to become a god and take on Aido in the past.
- Eldritch Abomination: A horrifying entity is glimpsed in a vision right before the town at the base of the mountain is destroyed. It's actually the cult leader Kagero Aido himself after he ascended to become some sort of dark deity.
- Evil Counterpart: Kagero Aido is a clear one to Father Miguel, with both being long-haired men who lead groups who obtain a matching hair color from mystical volcano fibers. Miguel is the Messianic Archetype of the story, while Aido turns out to be the Satanic Archetype from the villagers' terrifying vision.
- A God Am I: Kagero Aido becomes hungry for the knowledge of the entire universe, and believes he will become its creator once he does so, dismissing the idea that God is supreme.
- Godiva Hair: In Yukio's fevered visions of Kyoko, she appears nude with her amagami hair covering her breasts.
- Gone Horribly Right: The followers in Aido's second cult are given visions of the universe of the kind they desire, but their minds utterly break under the revelation and reduce them to madness.
- Go Mad from the Revelation: Dr. Kurodera concluded that Kyoko put herself in a state of bliss because the amigami hair was delivering an overload of information to her. While she eventually learned to block it off, his son Yukio was driven to use hypnotherapy and telepathy to connect with Kyoko. The end result turned him into an Eldritch Abomination.
- Hair of Gold, Heart of Gold: The amagami, indicated to be a blessing from Father Miguel, matches his golden hair and gives its beneficiaries a blissful sense of the universe. In contrast, Kagero Aido and his followers have black amagami and a selfish, destructive quest to obtain all of the universe's knowledge.
- Heroic Bystander: Wataro at first runs after Kyoko to interview her for a news story. When a cult kidnaps them both and ties her to a cross, however, Wataro seeks the first opportunity to untie her and pull her out from the church as it starts burning. He spends the rest of the story seeking her out, convinced she's in some kind of horrible danger.
- Humans Are Flawed: Unlike most of Ito's works, Sensor takes this approach. We see a wide range of people, from the kind search and rescue workers that get Kyoko to a hospital after finding her to the cult leader Kagero Aido, and those in the middle like Rie who is kind to strangers.
- Interrupted Suicide: Invoked. The teahouse owners and staff keep an eye on people in the town with the suicide bugs, noting any that stand over the cliff. If someone is there too long, they take them to the inn and treat them to tea.
- Meaningful Name: Mount Sengoku, the backdrop to a persecuted Christian village, is named for the Sengoku Period, an era of Japan during which Christianity started to arrive in the country.
- The Meaning of Life: The followers of Father Miguel believe the meaning of life is to observe and adore the universe with the powers granted by the amagami.
- Messianic Archetype: Father Miguel is a leader of oppressed Christians who has long hair and a beard like typical depictions of Jesus, and dies on a cross because of his faith, becoming a martyr for his people.
- No Good Deed Goes Unpunished: All those people that helped Kyoko while she traveled, including kindly Dr. Kurodera, Rie, and Wataro? The second cult kidnaps them and reduces most of them to skeletons with a mass meditation to find Kyoko.
- The Omniscient: Kyoko Byakuya becomes a vessel for all of the information in the universe after surviving the eruption. She struggles to block the flow of information, and Kagero Aido's cult tries to meditate through her to access the Akashic records of the universe.
- Sole Survivor:
- Dr. Kurodera, the psychiatrist that treated Kyoko, reveals that he came from the village Kiyokami that got caught in a volcanic eruption sixty years ago. He has a single strand of amigami in his hair, which he hoped would provide insight into treating Kyoko.
- In the climax, only Dr. Kurodera and Wataro survive the mass meditation while the other people who helped Kyoko are reduced to skeletons.
- Squick: The people in the town where the "suicide bugs" are showing up are revolted by them, both because of their freaky appearance and because of how they splatter when they're stepped on. One woman accidentally steps on one with her bare foot and screams in horrfied disgust.
- Stalker with a Crush: Beniko Yamaoka is a stalker of Wataro who starts showing up in his dreams and writing him precise letters of his doings. She turns out to be a member of the new cult with her own flavor of psychic powers, and has resumed stalking Wataro to track down Kyoko Byakuya.
- Timey-Wimey Ball: The story starts with Kyoko finding a village which shouldn't exist, being destroyed sixty years ago and seeing a vision of a dark god. After she survives, she gets taken in by a cult using her powers to access the Akashic records of the universe. By the end of the story, she has gone further back in time with the cult leader to the time before the village was destroyed, and Kyoko sacrifices herself to combat the cult leader, who turns out to become the vision of the dark god seen at the beginning.
- You Leave Him Alone!: When suicide bugs stalk Rie and speak in her ex's voice, Kyoko takes action for the first time in months. She shouts at them to stop harassing Rie and leads them away to the cliff. She jumps so that they will follow her and stop plaguing the town.
