From Okazu:

Asuka has returned from America, eighteen years in real time, and about 3 months later manga time. And immediately weird stuff begins to happen. Strange markings are being drawn upon people, things and buildings around Tokyo. The Area Masters, the leaders of the gangs in each section of Tokyo, are hearing strange whisperings about Hibari's new favorite, and about a possible takeover of power among themselves. And in the middle of all this, Asuka strolls in, with her studied nonchalance, and hyper-mad gang fightin' skillz, and basically turns everyone on their heads.