Actions take place in 2010 in the city of San Fierro. Life for Frank (you play as him) and Sean - two best friends develops as usual: shootouts with the mafia, weapons, showdowns (once they annoyed the triads, and now they take revenge with all their might) ... But Sean decided to intercept the van with weapons that the ballas were carrying to the mafia. Everything went well. Then Sean calls Frank and makes an appointment, and when he arrives at the place, the fun begins.
P.S. In the story there are not only main missions, but also additional ones that make the game more diverse. For example, you can complete missions with Sean and other characters at the same time, as well as run your own business.