Based on the 1995 book by Jonathan Harr, it tells the true story of a court case about environmental pollution that took place in Woburn, Massachusetts in the 1980s.

A lawsuit was filed over industrial operations that appeared to have caused fatal cases of leukemia and cancer, as well as a wide variety of other health problems, among the citizens of the city.

Environmental toxicants in the city of Woburn, Massachusetts, contaminate the area's water supply and become linked to a number of deaths of local children.

Cocky Boston attorney Jan Schlichtmann and his small firm of personal injury lawyers are asked by Woburn resident Anne Anderson to take legal action against those responsible.

Jan decides to go forward against two giant corporations that own the tanneries—Beatrice Foods and W. R. Grace and Company—thinking the case could possibly earn him millions of dollars and boost his firm's reputation.

The lawyers for Beatrice and Grace are not easy to intimidate, a judge makes a key ruling against the plaintiffs, and soon Jan and his partners find themselves in a position where their professional and financial survival has been staked on the outcome of the case.

A postscript reveals the EPA, building on Jan's work on the case, later brought its own enforcement action against Beatrice and Grace, forcing them to pay millions to clean up the land and the groundwater.