On board the train to Tokyo to meet her boyfriend Shoji, Nana Komatsu ("Hachi") happened to sit beside Nana Osaki who was traveling to Tokyo to fulfill her dreams of becoming a musician. The vocalist for her punk band "Blast", Nana aims for a major debut for "Blast" in Tokyo where her boyfriend, Ren, is the guitarist for a popular band "Trapnest". Sharing the same name "Nana", both girls quickly form a bond of friendship. Their paths cross again when they encounter each other while searching for accomodation in Tokyo. Eventually they decide to live together in the same unit and this further strengthens their bond as the two "Nana(s)" go through their love lives and career.