Grand Theft Auto: Vice City Stories is a 2006 action-adventure game developed by Rockstar Leeds and Rockstar North, and published by Rockstar Games. The tenth entry in the Grand Theft Auto series, the game was initially released as a PlayStation Portable exclusive in October 2006. A PlayStation 2 port was released in March 2007. Set within the fictional Vice City (based on Miami) in 1984, the game is a prequel to 2002's Grand Theft Auto: Vice City (set in 1986) and follows the exploits of ex-soldier Victor "Vic" Vance, a minor character originally featured in said game. The story centres around Vic's attempts to build up a criminal empire alongside his brother Lance. With the initial intention of raising money for his sick brother Pete's medication, Vic comes into conflict with rival gangs, drug lords and other enemies. In addition to the traditional gameplay elements and side missions of the series, the game features a unique empire building system, in which players must expand their criminal syndicate from the ground-up by taking over businesses from rival organizations, and completing missions specific for each of them to increase their income and unlock additional rewards. Like its predecessor, Grand Theft Auto: Liberty City Stories, the PSP version of the game includes a multiplayer mode through a wireless ad hoc network, which allows up to six players to engage in several different game modes. Vice City Stories received generally positive reviews from critics, and has sold over 4.5 million copies as of March 2008, making it the second best-selling PSP game of all time, after Liberty City Stories. The next game in the series was Grand Theft Auto IV, which was released in April 2008.