A story of 2 girls both named Nana meeting on a Tokyo-bound train. As friends the Nanas settle in one apartment despite their opposite characters and ideals.
20-year-old punk singer Nana Osaki is debuting with Black Stones (BLAST). She cultivates this new band after losing her musician and lover Ren who left to join the popular Tokyo band Trapnest (Taranesu in Japanese).
Nana Komatsu (called Hachi after Hachiko) is a weak-willed girl vulnerable to love at first sight and dependent on help. She is going to her friends and boyfriend after a year.
With the success of Black Stones in the background, romance issues between the Nanas develop with one seeking fame and the other seeking love.