While heading home, high school teacher Satoru Mizukami stumbled upon three cats and a mysterious girl named Mio, about 15 years old, left alone by the roadside. Bringing them into his care, Satoru discovered that Mio had amnesia but possessed an extraordinary ability to converse with felines, coupled with an impressive depth of otaku expertise. Unbeknownst to them, this peculiar situation stemmed from a diabolical plot orchestrated by angels from the celestial realm. The tale unfolds as the destinies of Mio, Satoru, and the cats intertwine in a captivating journey of mystery and revelation.