Erin Brockovich is one of those lone justice crowd pleasers, like ''Norma Rae'' or ''Silkwood,'' in which a workaday woman dares to fight the system because she's too stubborn, or foolhardy, to know that she's not supposed to. Julia Roberts' feisty, take no prisoners Erin coerces her way into an entry level job at a scruffy Los Angeles law office, where the attorney in charge is a middle aged ulcer candidate named Ed Masry, played subtlely charming by (Albert Finney).

Assigned to do some paperwork on what looks like a trivial pro bono case, Erin stumbles upon a hidden epidemic. Dozens of residents in nearby Hinkley have fallen victim to multiple tumors, degenerative organs, and other freak afflictions, yet no one has surmised that the wave of catastrophic illness might have something to do with Pacific Gas & Electric, the industrial plant on the edge of town. With little to go on but her gut, Erin learns that PG&E has employed a deadly form of chromium as an antirust agent, thereby contaminating the local water supply.

Why does Erin alone see through the company's lies? Mostly because of how torn up she is over the victims. She's wounded by their plight, especially that of the tremulous, naive Mrs. Jensen (played with touching vulnerability by Marg Helgenberger). The result is that her investigation never feels overtly noble or righteous; it's a matter of sheer empathetic will.

''Erin Brockovich'' is based on a true story. The movie is consistently engrossing. Its surprise -- and its pleasure -- is the plainspoken humanity of its outrage, its utter absence of demagoguery and hype. The arc of the tale may be conventional, but Roberts, in her most forceful dramatic performance, allows us to take in every moment through fresh, impassioned eyes.

Erin Brockovich herself, (a waitress in the diner scene) who speaks as passionately and powerfully in the DVD extra as Roberts performed on screen, is to be heroically lauded against villainous corporations and an apathetic legal system. She also answered a question I had about the real story, "This was not about the money. This was about them. They as a people came together, united, and fought for themselves, their children and their children's children."