When he intervenes in a domestic brawl, LAPD detective Shane Scully winds up killing his former partner. Now that he's violated the cardinal sin--killing a cop--Scully is ostracized by everyone on the force. Internal Affairs goes after him with a vengeance. To save his career, Scully is forced to offer them some dirt about his precinct, and he winds up discovering much dirtier laundry than he ever expected to find. Now his life is in danger, as is the life of Chooch, the adolescent son of a beautiful informant named Sandy.