Young Shinichiro once had a chat about alternate realities with a local cat on a hot summer day. Years later, he discovered another cat who can speak the language of humans, and a door opens to a whole new world. Unfortunately, his guide to learning how to be a modern day Doctor Dolittle, is the unflappable and occasionally hostile Narusawa, who warns Shinichiro that his decision to learn how to talk to animals may have consequences beyond his imaginings. It all seems like fun and games at first, especially with the charming black cat, Acht, around to liven things up, but as Shinichiro and Narusawa grow closer, the complexity of both communication and the human heart begin to be revealed...