During the summer vacation of their final year of high school, childhood friends Nana Chigusa and Kaoru Sugimura keep up the secret S&M sessions that bind them. Honor student Nana lets Kaoru take the master's role during the stolen hours they call a "breather," and a stay in the countryside pushes the arrangement further than either has taken it. This spin-off runs alongside the main Nana & Kaoru series, with a heavier focus on the pair's bondage play and the trust it demands.