Mao - Season 1

Nanaka Koyo is a third-year middle school student living in the modern Reiwa era. She wanders into an unfamiliar world through the gates of the Gogyo Shopping Street and meets a young man named Mao. After defeating a demon that attacked Nanaka, Mao tells her, "You're a demon, aren't you..."

Having remembered seeing a monster in an accident she was in when she was in first grade, Nanaka realizes that the world connected to the gate of the Gogyo Shopping Street is the Taisho era. Meanwhile, Mao begins investigating the "headless incident," which seems to be related to the cat demon that cursed him.

Nanaka, who doesn't die even when she touches Mao's "Sword of the Destroyer Star," may have been cursed after being exposed to the blood of a cat demon when she was a child. Nanaka returns to the modern Reiwa era and begins investigating the accident that happened to her eight years ago.

Nanaka and Otsuya infiltrate the Shōrin Sect, which seems to be connected to the Cat Demon. In the basement, they find a manuscript of sorcery, but it does not contain any instructions on how to manipulate people's lifespans. Then, the sect's leader, Shōko, locks the two of them in the basement.

In the Taisho era, earthquakes frequently struck Gogyo Town. Mao and Otsuya, who had gone to check on the collapsed hillside behind the town, heard from a yokai that a strange Western-style mansion had been built near where the keystone used to quell earthquakes had been enshrined. When the two visited the place, they found a church standing there, which should not have been there.

Nanaka tells Mao and Otsuya that she came from 100 years in the future, but they don't believe her. Returning to the present, Nanaka drinks the antidote given to her by Mao and remembers the day of the accident eight years ago. With doubts lingering, Nanaka heads to the Taisho era to meet Mao…

In the Taisho era, a younger version of Nanaka from eight years prior suddenly appears before her. The cat demon grabs the young Nanaka in its mouth and flies away through the gate of the Gogyo Shopping Street to the Reiwa era. In order to protect the young Nanaka, Mao, in his beast form, sends a guardian shikigami to the present day, but then faints.

Mao and his companions are attacked by their senior disciple, Hyakka, who wields fire magic. Hyakka dies once but immediately comes back to life. Hyakka has also been alive for 900 years. According to Hyakka, 900 years ago, five disciples were summoned to the "Goshikido" by their master.

Mao and his companions rush to the scene when Tenko is hit by a car driven by Ibaraki Tanehiko, who kidnaps young girls. There, a man named Kuchinawa appears, having been hired by the head of the Ibaraki family. Kuchinawa uses wood-based yin-yang magic, but his true identity is Kamon, Mao's senior disciple.

Mao sets a trap to lure out the shikigami user by making the attacking shikigami drink a talisman. Suddenly, a giant made of fish and water appears. The giant demands that Mao teach him the ultimate secret technique of Onmyodo, "Taizan Fukun," which allows him to manipulate people's lifespans.

The mother of a boy named Shigeru visits Mao's clinic, asking him to examine her son. Mao goes to see Shigeru, but it turns out to be a trap to lure him out. A water-manipulating shikigami attacks, attempting to capture Mao

Attacked by a water shikigami, Mao is reminded of the greatest water sorcerer of the Mikage family from the Heian period, but is confused as to why that sorcerer would send an assassin. Meanwhile, Kamon infiltrates the floating temple where the Mikage family's onmyoji is said to reside and is reunited with Shiranui.

Entrusted with a message for Mao from a cat demon that appeared in the Reiwa era, Nanaka heads to the Taisho era. Hyakka and Kamon are visiting Mao's clinic. Kamon reveals that the one running the fraudulent business under the guise of life extension was Shiranui, a water sorcerer.