Aki, a college student residing in Tokyo, is taken aback when an adolescent girl bursts into his apartment in a seemingly familiar manner. The revelation that follows is even more perplexing. The said "adolescent girl" is none other than Aki's beloved feline companion, Mill, who hails from his hometown Kyuushuu. To add to the oddity, Mill is an 86-year-old "monster cat" with shape-shifting abilities. Can Aki seamlessly integrate his paranormal feline into his regular college routine?