Kaoru is a 17-year-old virgin who has an SM fetish. He secretly dreams about an SM relationship with his childhood friend Nana. One day Kaoru's mom asks Nana to hide all his SM toys so he'll study for a change. However, Nana finds the leather one-piece that Kaoru bought and tries it on, but she accidentally locks it and doesn't have the key! The beginning of super strange relationship.

Due to the popularity of Nana to Kaoru, the series resumes publication in Young Animal and chapter 22 is the final chapter in Young Animal Arashi. Publication of the series will continue in Young Animal, but renumbered as chapter 1 while maintaining the same name and storyline.