The Taisho era—a time steeped in romance, when people's hearts still knew compassion.
At Mayonaka High School, five seemingly ordinary (well… maybe) boys—Unzen, Sugayu, Ubana, Oshamanbe, and Aso—spend their days lazily lounging in the clubroom of the “Do-Nothing Club,” officially known as the Earth Defense Club, while living together in the student dorm, Kurotama Dormitory.
One morning, while the five are enjoying a bath at Kurotama Dorm, something slippery and moving emerges from the bathwater. After finally managing to catch it, they discover… a talking Pallas’s cat named Nuru!
Nuru claims to have come from a far, far future with a grave message: Earth faces imminent doom.
He says he came to warn them of the danger—but whether or not to fight for the planet is up to them.
Wait… isn’t that just shirking responsibility?! The skeptical Defense Club boys question his motives.
But Unzen, fired up, declares, “If it’s either way, I’ll do it! It’s the more haikara (stylish) choice!”
Moved by their free-spirited resolve, Nuru uses cat science to transform the five into the Haikara Roman Squad!
Meanwhile, lurking in the shadows is a mysterious trio known as the Bankara Elite Force—
villains with their sights set on world domination.