Two girls named Nana meet on a train to Tokyo. Nana K. aims to reunite with her boyfriend and Nana O. hopes to make it big in the music business. Despite their differences, the pair hit it off and become roommates.

Two girls with the same name but very different personalities share an apartment in this sequel to Nana. The rising fame of Nana Osaki's band, the Black Stones, is beginning to take a toll on the best friends' relationship. Meanwhile, Nana Komatsu struggles to make sense of her love triangle with Black Stones' guitarist Nobu and rival group Trapnest's bassist Takumi.