Nana Chigusa and Kaoru are in their third and final year of high school. As university entrance exams loom and the pressure to decide their futures mounts, their private ritual of SM play, which they call breathers, intensifies. Set after the events of the original Nana to Kaoru series and the Black Label arc, Last Year follows the couple as they navigate the final stretch of adolescence. Their secret bond deepens, but new complications arise from the involvement of other characters, including the writer Tachibana and the assertive Sarashina, who challenge the dynamics between Nana and Kaoru. The story gives greater weight to Nana’s perspective, exploring her anxieties about dependency, her fear of losing Kaoru, and her growing trust in him. Over the course of the year, both learn to understand their own desires more clearly. In the end, Nana and Kaoru reaffirm their commitment to each other, accepting that their unusual connection is an inseparable part of who they are, and look toward a future together.