SPOILER
Brian is freed from prison (the authorities found out that he let Dominic go at the end of the first film) to help the feds stop a heroin importer known as Braga. With the help of an informant named James Park, Brian - and ultimately both Dominic Toretto and Sean Boswell - win a place on the criminal's team, where he - and his flashy Nissan plan to catch the man red-handed.