Very little information about the game has been released of now except that it will be on the PSP. It seems that the game will mainly focus around Zack, a 1st Class SOLDIER and Cloud Strife while he is a lowly Shin-Ra Guard. Another character also present in the game is Aerith Gainsborough as her voice is heard in the trailer of the game. This game appears to take place around the events of Nibelheim outlined in Last Order: Final Fantasy VII.

The game's tagline: "A story of three young men and one young woman bound for destiny's core."

From details that have been shown it is safe to say this is Zack's story and will cover the events between the supporting characters Sephiroth, Cloud, Angeal, Aerith, Tseng, and Genesis, as well as other characters with minor roles (such as the other Turks and the other main characters of Final Fantasy VII) up until the events of Nibelheim. Any other futher details about the story are yet to be revealed. Yet a major plot point hinted at in the final chapter of Final Fantasy VII universe, Dirge of Cerberus, were the 3 G Reports, the only records left of the Genesis Project and its aftermath. Within the three brief reports it reveals a project performed by Shin-Ra on a SOLDIER only known as "G". It also discussed the whereabouts of "G" (a.k.a. Genesis), that he was sealed deep under Midgar by a SOLDIER who died in order to defeat him. That SOLDIER that managed to defeat Genesis was most likely Angeal, which explains how the Buster Sword eventually ends up in Zack's possession.

( Reference: http://www.square-enix.co.jp/games/psp/ccff7/ )