Shinichi Chiaki, the brilliant and perfectionist conductor, has finally achieved his dream of working in Europe after overcoming his fear of flying. He and the eccentric but gifted pianist Megumi Noda, known as Nodame, have relocated to Paris, where Chiaki has won the prestigious Platini International Music Competition. As the story of Nodame Cantabile Saishū Gakushō begins, Chiaki is appointed the new conductor of the struggling Le Marlet Orchestra in Paris. The ensemble has lost many of its members and its audience due to lack of funding and poor performance standards, presenting Chiaki with his most challenging professional obstacle yet. Meanwhile, Nodame is preparing for her graduation exam at the Conservatoire de Paris, striving to improve her technical skills to stand beside Chiaki as an equal rather than remaining just his devoted and messy follower.

The two films, Zen-Pen (The Final Score Part I) and Kou-Hen (Part II), follow their parallel journeys of artistic maturation. Chiaki works relentlessly to rebuild the Le Marlet Orchestra, conducting auditions and instilling discipline in the ragtag group. His first performance with them, featuring Ravel's Bolero, becomes a humiliating failure when the audience laughs at the orchestra's incompetence. The disappointment forces Chiaki to reevaluate his approach and remember the lessons he learned from his eccentric teacher Franz Stresemann and from leading the S Orchestra back in Japan. Nodame, initially thrilled when Chiaki asks her to perform Bolero with the orchestra, experiences crushing disappointment when the brilliant pianist Rui Son takes her place in the performance. This setback, combined with the pressures of her conservatory studies, leads Nodame to question whether she can ever truly catch up to Chiaki.

The narrative arc intensifies as both characters confront their limitations. Nodame throws herself into preparing for a major piano competition, hoping to prove herself. Her determination leads her to temporarily separate from Chiaki, as she needs to focus entirely on her music. The piece she selects for the competition is Ravel's Piano Concerto in G Major, a technically demanding work that pushes her to her limits. During this period, Chiaki faces his own trials when Rui Son, a gifted pianist who shares his intense and perfectionist nature, becomes the soloist for the Le Marlet Orchestra. The professional and emotional tension between Chiaki and Rui creates a rift that distances him from Nodame just when she needs his support most.

The story culminates in a powerful convergence of their separate struggles. Nodame delivers a transcendent performance of the Ravel concerto, finally understanding how to blend her natural, free-spirited playing with the discipline Chiaki has taught her. She no longer plays just to be with Chiaki but because she has found her own voice as an artist. Chiaki, witnessing her growth, realizes that his feelings for her run deeper than professional admiration. The films conclude with Chiaki conducting a triumphant concert with the reformed Le Marlet Orchestra, and the two musicians finally acknowledging their mutual love and respect. They return to Japan together, no longer as teacher and student or as two people chasing different dreams, but as partners who have each achieved artistic maturity while remaining connected by the music that brought them together. The supporting cast from the television drama, including the flamboyant violinist Ryutaro Mine, the devoted timpanist Masumi Okuyama, and the quirky members of the original S Orchestra, make appearances throughout, showing how the bonds formed at Momogaoka College of Music continue to influence and inspire Chiaki and Nodame even as they navigate the demanding world of professional classical music in Europe.