Nana Osaki is a punk singer who wants to debut with her band Black Stones (BLAST for short). Nana was the lead vocalist in their old band with her boyfriend, Ren, and they lived together as lovers since she was 16. When Ren was offered a chance to debut in Tokyo as a replacement member of the popular band Trapnest (Toranesu in Japanese), Nana chose to cultivate her own band after Ren left her and Black Stones for Trapnest. Having too much pride to simply follow Ren to Tokyo and happily be a rockstar's girlfriend, she stayed behind. She leaves for Tokyo at the age of twenty, and to start her musical career.
Nana Komatsu, the other Nana, is called with the nickname Hachi (after Hachikō as she has weak mental characteristics that resemble a puppy. With a habit of falling in love at first sight all the time, Hachi has always depended on other people to help her. When her friends and then boyfriend leave for Tokyo, she decides to join them a year later after having saved enough money at the age of twenty.
Nana and Hachi meet in a train by chance, both on their way to Tokyo. After a string of coincidences, they come to live together in an apartment numbered 707. Despite having contrasting characters and ideals, the Nanas like and respect each other.
While the Black Stones begin to gain popularity at live gigs, other issues need resolving, especially in the areas of romance. The story of Nana revolves heavily on the romance and relationships of the two characters as one seeks fame and recognition while the other seeks love and happiness
as she has weak mental characteristics that resemble a puppy. With a habit of falling in love at first sight all the time, Hachi has always depended on other people to help her. When her friends and then boyfriend leave for Tokyo, she decides to join them a year later after having saved enough money at the age of twenty.
