I just bought Famitsu and I have a few more details about the story:
As the rumors said the story will be placed in December 1988 at Kamurocho and Soutenbori.
In that period there was a fight to get the contract to build the Milleium Tower.
An evening, Kiryu collects money from a person that suddently get murdered.
Tojo-kai suspect the killer was Kiryu and they point the spearhead to Kazama too.
To protect him, Kiryu decide to leave Doujima-gumi, but...
In the meantime, Majima lives in Osaka and manage a Cabaret Club in Soutenbori under Oumirengo protection.
Majima is hiding himself from Tojo-kai (you know the reason if you played Yakuza 4), but he still dream about go back into yakuza.
One day he receive an offer, he can return into yakuza if he kills a person...