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.

Mika Nakashima
as Nana Osaki

Aoi Miyazaki
as Nana Komatsu (Hachi)

Kenichi Matsuyama
as Shinichi Okazaki

Ryuhei Matsuda
as Ren Honjou

Tetsuji Tamayama
as Takumi Ichinose

Tomomi Maruyama
as Yasushi Takagi

Saeko
as Sachiko Kawamura

Yuna Ito
as Reira Serizawa

Momosuke Mizutani
as Naoki Fujieda

Anna Nose
as Junko Saotome