Riko and Rimu Mikogami are twin sisters who live in Kamihama, a Japanese city abundant with natural wonders. On an otherwise peaceful day, while searching for a run-away cat, the two come across a mysterious Kirumin compact in an attic. With the Kirumin, these character-costume-wearing girls can transform into real animals. Their older sister Nagisa Mikogami soon joins them. Now the three have cute, funny and sometimes dangerous adventures while solving a lot of mysteries they encounter.

Kawamori's theme for the anime is: "What if you can really transform into an animal?"