Both legal thriller and heartbreaking human rights drama, Joe Berlinger’s latest documentary examines the so-called Amazon Chernobyl case, a 16-year-old lawsuit waged by the indigenous people of Ecuador against Chevron for the widespread pollution of their lands and waterways. As with Berlinger’s acclaimed courtroom docs Brother’s Keeper and Paradise Lost, the director presents evidence from both sides, but ultimately mounts his own vigorous defense for the oppressed. (Here, an image of a trembling, helpless duck is indelible.) The film’s spine belongs to the maneuverings of Ecuadoran lawyer Pablo Fajardo and his rambunctious Manhattan adviser Steven Donziger, who mobilize the media, Ecuador’s new president, and even rock star Sting and his wife, Trudie Styler, in their fight. By movie’s end, David may not have beaten Goliath, but as Donziger says, at least the underdog is in the game.