In the Nana to Kaoru: Black Label series, the timeline jumps eight months ahead from the original plot. Nana and Kaoru are now in their final year of high school, taking a hiatus before their college admission tests begin. They pass their days engaged in their special indulgence called "breathers", despite their friends' other interests. However, Nana's inquisitiveness leads her to a store specializing in S&M, where she encounters Tachibana, an employee. This sparks her interest in the BDSM lifestyle, and she gains knowledge about the dynamics of master and slave relationships.
