Nana Komatsu is a helpless twenty-year-old who easily falls in love and becomes clingy to those around her. She ends up traveling to Tokyo to chase her current boyfriend Shouji Endo. Nana Osaki, on the other hand, is a proud, enigmatic punk rock vocalist from a similarly rural background, who nurtures the desire to become a professional singer. Putting her career with a fairly popular band firmly behind her, she boards the same train to Tokyo as Nana Komatsu. Through a fateful encounter in their journey toward the metropolis, the young women with the same given name are brought together, sparking a chain of events which eventually result in them sharing an apartment. As their friendship deepens, the two attempt to support each other through thick and thin, their deeply intertwined lives filled with romance, music, challenges, and heartbreaks that will ultimately test their seemingly unbreakable bond.