Tachibana Hinata and Jinguuji Tsukasa have been best friends since childhood. Now, at 32 years old, they're both average businessmen. One night after a mixer, an entity calling itself a goddess sends them to another world. When Jinguuji opens his eyes, he sees Tachibana, who's been transformed into a beautiful, blue-eyed, blonde girl. Now that the two are of different genders from each other, they're each bewildered by the other's charms. They steel their determination to defeat the Demon Lord in order to return to who they were with their relationship still intact.