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.

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.

Futakotamagawa High School had a Baseball Club, but because of a fight during one of their games, they were suspended for a year from all games. Composed of student delinquents, Futakotamagawa High's new Literature teacher Kawato Koichi inspires the Baseball Club to believe in a dream goal once again. For them, it is to play at the Koshien - Japan's National High School Baseball Championship. But, Kawato Koichi and the newly reformed baseball team run into plenty of obstacles along the way...

On September 9th, the day of the Katakai Fireworks Festival, high school student Hana comes home from the hospital after six months of treatment for leukemia. She then discovers that her older brother Taro has become a social recluse. Taro used to be tender, smart and proud of his younger sister, but now he even turns his back on her and stays in his room. With Hana's help Taro slowly opens up to the world again. Then, with winter approaching, Hana has a relapse with her leukemia. Taro comes to the hospital everyday to visit Hana and soon learns that the Katakai Fireworks Festival is a symbol of happiness for Hana. Taro then takes the initiative to make Hana happy and approaches the town's youth group once more for admittance.