Summer Arc

The first twelve episodes of the series focus on the day-to-day life of Ayumu Aizawa as he visits his father, a veterinarian, in a small town in the countryside. Ayumu has spent his visit thus far aimlessly biking across the valley, but a chance meeting with a girl named Miku sends him searching for a long-lost friend of his, Wakkun. Upon finding Wakkun, he discovers that the boy has not aged since he and Ayumu played as children. Wakkun is also wearing clothes very similar to the raincoat and galoshes that Ayumu wore habitually as a child. Wakkun introduces Ayumu to his two friends, Dosshiru (Doss) and Shisshin (Sense), mysterious flying objects that alternate between a mechanical form and a sphere of yellow light.

These lights seem to be invisible to most of the people in town, but appear in reflections in people and animals' eyes. A local reporter, Akira Sukawara, shows up, attracted by reports of kappa and other mysterious events. She follows the animals, notably a cat one of the local boys saw fighting a kappa, to the yellow lights, and grills a reluctant Ayumu for information. Unable to remember the summer he spent in Tana as a child, Ayumu, with the help of Miku and several other people from Tana, tries to understand what happened when he was a child, and the mysterious connection between him, Wakkun, Dosshiru, and Shisshin...

Winter Arc

One and a half years later, Kisa Tanigawa, a depressed high school student, routinely skips class. One evening, wandering aimlessly around the city, she stumbles upon another mysterious mechanical object. Naming it "Bun-chan" or "Ping" in the English dub, after the sound it makes, she takes it home and treats it as a pet. When she tries building a fish out of old scraps of metal, the top fin of the fish does not stay, so Bun-chan (Ping) helps glue it on. Meanwhile, Sukawara reappears, now trying to prove the existence of the mysterious objects that appeared at the Cat Dance in Tana a year and a half ago, which she terms "material fairies", and hears about Bun-chan. Upon witnessing a meeting between Kisa and Ayumu, she calls Bun-chan not a material fairy, but a "material evil", as its outward appearance does not resemble those of the material fairies spotted in Tana. The material fairies and the material evils, however, seem to be at war with each other. When the three meet, Dosshiru, Shisshin and Bun-chan. Dosshiru and Shisshin start chasing Bun-chan and soon destroy it, leaving Kisa very upset that Bun-chan is gone. After a while the connection of Kisa's fish's metal fin starts glowing. One night the fish turns into a sprite form of Bun-chan. Kisa then decides to name it Po-chan.

The city's population becomes increasingly aware of the situation, as pictures of the material evils, spheres of blue light, circulate among cell-phone users, accompanied by rumors that they bring good luck. Murals appear urging people to think and trust themselves. Eventually, a giant spiral, resembling the metal construction of the material evils, appears in the sky, and the police evacuate a section of the city. Some of the same phenomena are present in Tana, such as the failure of electronic devices.

Summer Arc

Ayumu Aizawa (逢沢歩, Aizawa Ayumu)

Voiced by: Toshiyuki Toyonaga

Miki Miyama (深山美紀, Miyama Miki)

Voiced by: Kanako Mitsuhashi

Miku Miyama (深山美玖, Miyama Miku)

Voiced by: Chiwa Saitō

Ryūsuke Sakakura (阪倉亮介, Sakakura Ryūsuke)

Voiced by: Yakkun Sakurazuka

Shione Unno (海野潮音, Unno Shione)

Voiced by: Ai Shimizu

Takuma Kaburaki (鏑木拓馬, Kaburaki Takuma)

Voiced by: Yasuyuki Kase

Wakkun (わっくん)

Voiced by: Junko Takeuchi

Heigorō Suzuki (鈴木平五郎, Suzuki Heigorō)

Voiced by: Katsuhisa Hōki

Asako Tōdō (藤堂麻子, Tōdō Asako)

Voiced by: Risa Mizuno

Akira Sukawara (須河原晶, Sukawara Akira)

Voiced by: Miwa Matsumoto

Mika Miyama (深山美佳, Miyama Mika)

Voiced by: Masami Suzuki

Akiyuki Kishiro (稀代秋之, Kishiro Akiyuki)

Voiced by: Kenji Hamada

Junko Aizawa (逢沢淳子, Aizawa Junko)

Voiced by: Kaori Yamagata

Shirō Dōmaru (堂丸史郎, Dōmaru Shirō)

Voiced by: Tadahisa Saizen

Okaka Baba (オカカ婆, Okaka Babā)

Voiced by: Yakkun Sakurazuka

Taruto (タルト, Taruto)

Voiced by: Ai Shimizu

Roku (ロク, Roku)

Voiced by: Katsuhisa Hōki

Mikoshiba-san (御子柴さん)

Winter Arc

Ayumu Aizawa (逢沢歩, Aizawa Ayumu)

Voiced by: Toshiyuki Toyonaga

Kisa Tanigawa (谷川希紗, Tanigawa Kisa)

Voiced by: Akiko Kobayashi

Rieko Yamato (大和理絵子, Yamato Rieko)

Voiced by: Tomoko Sadohara

Masaki Makabe (真壁正樹, Makabe Masaki)

Voiced by: Yuki Kaida

Shigeki Kobayakawa (小早川成基, Kobayakawa Shigeki)

Voiced by: Takahiro Sakurai

Jirō Hatori (羽鳥次郎, Hatori Jirō)

Voiced by: Hozumi Gōda

Mika Miyama (深山美佳, Miyama Mika)

Voiced by: Masami Suzuki

Akira Sukawara (須河原晶, Sukawara Akira)

Voiced by: Miwa Matsumoto

Hana Tokimiya (土岐宮はな, Tokimiya Hana)

Voiced by: Misa Watanabe

Okaka Babā (オカカ婆, Okaka Babā)