It's the Taisho era—a time filled with the scent of romance, and people's hearts are still filled with compassion. Unzen, Sukayu, Unohana, Oshamanbe, and Aso are all ordinary (?) male students at Mayunan High School, who spend their days lazing around in the clubroom of the "do-nothing club" Earth Defense Club, and live together in the Kurodama dormitory. One day, while the five are taking a morning bath at the Kurodama dormitory, they notice something slimy moving in the bathtub. When they finally manage to catch it, it turns out to be a talking Pallas's cat named Nuru! Nuru has come from the distant future with a serious mission to inform them that the Earth is facing an impending threat of destruction. While he says he wants to protect the Earth, he says he's only come to warn them of the crisis, and that it's up to the five of them to decide whether or not they want to fight for the Earth... Isn't this just an attempt to dodge responsibility? The Defense Club members are suspicious. "If either is fine with you, I'll do it! That's more fashionable!" Unzen enthusiastically says. The five decide to fight with free will, and Nuru transforms them into the Fashionable Romantic Troupe using cat science. Meanwhile, a mysterious trio called the Bankara New Elite Squad are scheming in the shadows. They are plotting to take over the Earth.

After a fierce battle, Magic swordsman Kyle finally killed the Demon Lord after being seriously injured in the battle. Kyle on the verge of death approaches a relic which was in possession of the Demon Lord and it sends him to the past. After recovering from the initial shock, he decides to use this opportunity to avoid making the same mistakes of the past and become stronger.

Lua is a saintess candidate who possesses the power of healing. But her ability had one flaw: she could only heal others by transferring their wounds onto herself. Because of this, others bullied her, calling her the "Fallen Saintess." But it didn't bother Lua because her best friend Arianne always stood up for her. One day, Lua's crush, Commander Garrett, was on the brink of death from a beast attack. Lua healed him, which left her on the verge of death. When she woke up, she learned that all the credit was given to Arianne, and she finally saw her best friend's true color. Devastated, Lua is lost and helpless when the second prince appears in front of her with a tempting offer. What would happen to Lua as she begins her new life as a villainess?

Takeru Narihira is a lone wolf delinquent who spends his days getting into fights, avoiding friendships, and being captivated by a mysterious girl named Tsukimiya—someone he's only ever seen in his dreams. One day, a sudden accident sends him tumbling off a cliff. When he regains consciousness, he finds himself in Denji Heian-kyou, a futuristic version of the ancient capital, where advanced technology and mysticism coexist. This world is under the protection of the legendary onmyouji, Abe no Seimei—and to Takeru's shock, Tsukimiya is real and living in this very place. Just as he begins to revel in this fated encounter, a deadly black mist known as Yamikaoru descends, bringing forth monstrous beings called Oni. In the chaos, both he and Tsukimiya are killed—only for Takeru to awaken once again in Denji Heian-kyou. Realizing he has somehow slipped through time, Takeru resolves to defy fate. To protect Tsukimiya from her doomed future, he turns to Abe no Seimei to train in the art of onmyou-jutsu. Now, as an onmyouji himself, he must fight to rewrite destiny and uncover the truth behind this strange new world.